Quiz 6: Applications of Newtons Laws

You are driving in your car with a sack of groceries in the seat next to you. You see a light change and you slow down and the sack remains on the seat. Suddenly the car in front of you slams on the brakes, and you are forced to brake harder. The groceries slide off the seat. Explain what happened.

State the condition for an object to be in translational equilibrium.

Is it possible for an object moving with a constant speed to accelerate? Explain.

An airplane is flying with constant speed along a horizontal circle. Is the direction of its acceleration constant?

Why does a cyclist tilt her bicycle on a curve?

You are driving your car and set your sunglasses on the dashboard. When you make a left turn, the sunglasses go sliding off to the right. Explain.

The force of kinetic friction between two surfaces is dependent on the relative speed of the two surfaces.

The force of kinetic friction between two surfaces is independent of the area of contact between the surfaces.

The coefficient of static friction is always larger than the coefficient of kinetic friction.

The force of static friction between two surfaces is independent of the area of contact between the surfaces.

The force fo static friction between two surfaces is parallel to the surface of contact, and in in the direction that opposes relative motion.

An ideal pulley changes the direction of the tension in a string without changing its magnitude.

The stretch of a spring and the force it exerts are inversely proportional.

When an object is in translational equilibrium, the net force acting on the object is non-zero.

A body moving with constant speed cannot be accelerating.

For uniform circular motion, the velocity and acceleration vectors are perpendicular to each other at every point in the path.

A net horizontal force is required for a body to move in a horizontal circle.

The banking angle for a properly banked curve does not depend on the mass of the car going over it.

When a curve is properly banked a passenger in a car traveling on it at the designed speed does not feel a lateral force.

An object moving along a curved path with constant speed does not have a net force acting on it.

Its more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because A) The normal force is greater when the carton is at rest. B) μ_s < μ_k. C) Initially, the normal force is not perpendicular to the applied force. D) μ_k < μ_s. E) μ_s = μ_k.

A packing crate slides down an inclined ramp at constant velocity. Thus we can deduce that A) a frictional force is acting on it. B) a net downward force is acting on it. C) a net upward force is acting on it. D) it is not acted on by appreciable normal force. E) it is not acted on by appreciable gravitational force.

If a car slows down with the wheels rolling, is the frictional force between the tires and the ground kinetic or static? A) kinetic B) static

When a car goes around a curve, it has a tendency to skid outwards. Is the frictional force between the tires and the ground that keeps the car from skidding kinetic or static? A) kinetic B) static

A flatbed truck is carrying a crate along a level road. The coefficient of static friction between the load and the bed is 0.40. The truck accelerates forward and the crate stays in its place on the truck bed. In what direction is the force that the bed exerts on the crate? A) forward B) backward C) toward the center of the road D) There is no frictional force because the crate does not move with respect to the bed. E) There is not enough information to answer this question.

As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is A) static friction. B) kinetic friction. C) a combination of static and kinetic friction. D) neither static nor kinetic friction, but some other type of friction. E) It is impossible to tell what type of friction acts in this situation.

FIGURE 6-1 -In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The force of static friction f must be such that A) f > mg. B) f > mg cosθ. C) f > mg sinθ. D) f = mg cosθ. E) f = mg sinθ.

FIGURE 6-1 -In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The normal force F acting on the block must be such that A) F > mg. B) F > mg cosθ. C) F > mg sinθ. D) F = mg cosθ. E) F = mg sinθ.

FIGURE 6-2 -In Figure 6-2 the scale at left is attached to the ceiling and a mass of 1.00 kg hangs from it. It reads 9.81 N. The identical scale at the right is connected by perfect strings passing over perfect pulleys to two 1.00 kg masses hanging vertically at the end of the strings. The scale at right reads A) exactly 9.81 N. B) more than 9.81 N, but not quite twice as much. C) less than 9.81 N. D) exactly 19.62 N. E) more than 19.62 N.

FIGURE 6-3 -Compare the two situations shown in Figure 6-3. On the left (A), James is holding the rope and keeping the bucket at rest. On the right (B), James ties the rope to the bucket so that it keeps the bucket at rest. In both cases the bucket contains the same quantity of water. In what case is the tension in the rope higher? A) left B) right C) It is the same in both cases. D) We need more data to answer.

FIGURE 6-4 -A 16-kg fish is weighed with two spring scales, each of negligible weight, as shown in Figure 6-4. What will be the readings on the scales? A) The bottom scale will read 16 kg, and the top scale will read zero. B) The sum of the two readings will be 32 kg. C) The top scale will read 16 kg, and the bottom scale will read zero. D) Each scale will show a reading greater than zero and less than 16 kg, but the sum of the two readings will be 16 kg. E) Each scale will read 8 kg.

FIGURE 6-5 -Two masses, m₁ and m₂, are connected to each other as shown in Figure 6-5. Mass m₁ slides without friction on the table surface. Both masses have acceleration of magnitude a as shown. How does the tension in the string compare to the weight, m₂ g, of mass m₂? A) The tension is equal to m₂ g. B) The tension is larger than m₂ g. C) The tension is smaller than m₂ g. D) It depends on m₁ being smaller than m₂. E) It depends on m₁ being larger than m₂.

FIGURE 6-6 -Two identical masses are attached by a light string that passes over a small pulley, as shown in Figure 6-6. The table and the pulley are frictionless. The masses are moving A) with an acceleration less than g. B) at constant speed. C) with an acceleration greater than g. D) with an acceleration equal to g. E) with an acceleration that cannot be determined without additional information.

When an object experiences uniform circular motion, the direction of the acceleration is A) in the same direction as the velocity vector. B) in the opposite direction of the velocity vector. C) is directed toward the center of the circular path. D) is directed away from the center of the circular path. E) depends on the speed of the object.

What type of acceleration does an object moving with constant speed in a circular path experience? A) free fall. B) terminal acceleration. C) constant acceleration. D) linear acceleration. E) centripetal acceleration.

When an object experiences uniform circular motion, the direction of the net force is A) in the same direction as the motion of the object. B) in the opposite direction of the motion of the object. C) is directed toward the center of the circular path. D) is directed away from the center of the circular path. E) is dependent on the speed of the object.

Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity. A) It is moving in a straight line. B) It is moving in a circle. C) It is moving in a parabola. D) It is moving in a hyperbola. E) None of the above is definitely true all of the time.

An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors. A) Both vectors point in the same direction. B) The vectors point in opposite directions. C) The vectors are perpendicular. D) The question is meaningless, since the displacement is zero. E) The question is meaningless, since the acceleration is zero.

For an object that travels at a fixed speed along a circular path, the acceleration of the object is A) larger in magnitude the smaller the radius of the circle. B) in the same direction as the velocity of the object. C) smaller in magnitude the smaller the radius of the circle. D) in the opposite direction of the velocity of the object. E) zero.

A roller coaster car is on a track that forms a circular loop in the vertical plane. If the car is to just maintain contact with track at the top of the loop, what is the minimum value for its centripetal acceleration at this point? A) g downward B) 0.5g downward C) 2g downward D) g upward E) 2g upward

A roller coaster car (mass = M) is on a track that forms a circular loop (radius = r) in the vertical plane. If the car is to just maintain contact with the track at the top of the loop, what is the minimum value for its speed at that point? A) rg B) 2rg C) (rg)^1/2 D) (2rg)^1/2 E) (0.5rg)^1/2

The banking angle in a turn on the Olympic bobsled track is not constant, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "climb the wall," then go lower coming out of the turn. Why do they do this? A) to give the team better control, because they are able to see ahead of the turn B) to prevent the bobsled from turning over C) to take the turn at a faster speed D) to take the turn at a slower speed E) to reduce the g-force on them

A 55.0-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.300. What horizontal force must be applied to the box for it to start sliding along the surface?

A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30. A 140-N force is applied to the box. What is the frictional force on the box?

FIGURE 6-7 -A 30.0-kg load is being lifted with constant speed using the ideal pulley arrangement shown in Figure 6-7. What is the magnitude of the force F?

A 30.0-kg load is being raised by a force of 180 N using the ideal pulley arrangement shown in Figure 6-7. What is the acceleration of the load?

A workman lowers a 30.0-kg load using the ideal pulley arrangement shown in Figure 6-7. He allows the rope to slide in his hands, thus exerting a downward force of 100 N on the rope. What is the acceleration of the load?

FIGURE 6-8 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-8. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of static friction between block A and the plane is 0.400. What mass should block B have in order to start block A sliding up the ramp?

A 60.0-kg mass person wishes to push a 120-kg mass box across a level floor. The coefficient of static friction between the person's shoes and the floor is 0.700. What is the maximum coefficient of static friction between the box and the floor such that the person can push horizontally on the box and cause it to start moving? A) 0.333 B) 0.500 C) 0.350 D) 0.667 E) 0.700

A child pulls a 3.00-kg sled across level ground at constant velocity with a light rope that makes an angle 30.0° above horizontal. The tension in the rope is 5.00 N. Assuming the acceleration of gravity is 9.81 m/s², what is the coefficient of friction between the sled and the ground? A) 0.161 B) 0.188 C) 0.0441 D) 0.0851 E) 0.103

A flatbed truck is carrying a 20.0-kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place? A) 3.92 m/s² B) 7.84 m/s² C) 8.00 m/s² D) 78.5 m/s² E) 196 m/s²

A flatbed truck is carrying a 20.0-kg crate up a sloping road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum angle of slope that the truck can climb at constant speed if the crate is to stay in place? A) 0.381° B) 13.1° C) 21.8° D) 23.6° E) 66.4°

A flatbed truck is carrying a 20.0-kg crate up a sloping road inclined 15.0° above the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place? A) 0.625 m/s² B) 1.25 m/s² C) 2.50 m/s² D) 3.16 m/s² E) 6.33 m/s²

A flatbed truck is carrying a 20.0-kg crate down a sloping road inclined 15.0° below the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place? A) 1.25 m/s² B) 0.625 m/s² C) 2.50 m/s² D) 3.16 m/s² E) 6.33 m/s²

A policeman investigating an accident measures the skid marks left by a car. He determines that the distance between the point that the driver slammed on the brakes and the point where the car came to a stop was 28.0 m. From a reference manual he determines that the coefficient of kinetic friction between the tires and the road under the prevailing conditions was 0.300. How fast was the car going when the driver applied the brakes? (This car was not equipped with anti-lock brakes.) A) 10.7 m/s B) 12.8 m/s C) 21.4 m/s D) 32.9 m/s E) 45.7 m/s

A 50.0-kg box is being pushed along a horizontal surface. The coefficient of kinetic friction between the box and the ground is 0.350. What horizontal force must be exerted on the box for it to accelerate at 1.20 m/s²? A) 60.0 N B) 116 N C) 172 N D) 232 N E) 491 N

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 30.0° below the horizontal is applied to the box. The coefficient of static friction between the box and the surface is 0.400. What is the force of friction on the box? A) 31.9 N B) 196 N C) 217 N D) 246 N E) 616 N

A baseball player is running to second base at 5.03 m/s. When he is 4.80 m from the plate he goes into a slide. The coefficient of kinetic friction between the player and the ground is 0.180. What is his speed when he reaches the plate? A) 4.47 m/s B) 2.89 m/s C) 1.96 m/s D) 2.56 m/s E) He stops before reaching the plate.

A 50.0-kg box is being pulled along a horizontal surface by means of a rope that exerts a force of 250 N at an angle of 32.0° above the horizontal. The coefficient of kinetic friction between the box and the surface is 0.350. What is the acceleration of the box? A) 0.638 m/s² B) 1.74 m/s² C) 3.16 m/s² D) 6.31 m/s² E) 8.53 m/s²

A 50.0-kg box is being pushed along a horizontal surface by a force of 250 N directed 28.0° below the horizontal. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box? A) 0.769 m/s² B) 1.77 m/s² C) 3.16 m/s² D) 6.31 m/s² E) 8.53 m/s²

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 20.7° below the horizontal is applied to the box. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box? A) 1.21 m/s² B) 1.77 m/s² C) 2.84 m/s² D) 3.54 m/s² E) 5.14 m/s²

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 26.0° below the horizontal is applied to the box. What is the minimum coefficient of static friction between the box and the surface required for the box to remain stationary? A) 0.441 B) 0.654 C) 0.375 D) 0.866 E) 0.406

A 50.0-kg block is being pulled up a 13.0° slope by a force of 250 N which is parallel to the slope, but the block does not slide up the slope. What is the minimum value of the coefficient of static friction required for this to happen? A) 0.115 B) 0.566 C) 0.654 D) 0.359 E) 0.292

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which is parallel to the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block? A) 0.528 m/s² B) 0.158 m/s² C) 0.412 m/s² D) 0.983 m/s² E) 0.260 m/s²

A 50.0-kg block is being pulled up a 15.0° slope by a force of 300 N which is directed 30.0° above the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block? A) 1.36 m/s² B) 0.158 m/s² C) 0.924 m/s² D) 0.520 m/s² E) 1.47 m/s²

A 50.0-kg block is being pushed up a 15.0° slope by a force of 300 N which is directed 30.0° below the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block? A) 0.164 m/s² B) 0.967 m/s² C) 1.20 m/s² D) 2.20 m/s² E) 0.528 m/s²

A box slides down a 25.0° slope under its own weight. The coefficient of kinetic friction between the box and the slope is 0.350. What is the acceleration of the box? A) 1.03 m/s² B) 2.06 m/s² C) 1.22 m/s² D) 2.20 m/s² E) 2.44 m/s²

FIGURE 6-9 -A 22.0-kg crate is pulled along a horizontal floor by the ideal arrangement shown in Figure 6-9. The force F is 300 N. The coefficient of friction between the crate and the floor is 0.270. What is the acceleration of the crate? A) 4.17 m/s² B) 6.57 m/s² C) 2.34 m/s² D) 4.85 m/s² E) 9.65 m/s²

Diff: 1 Var: 5 Page Ref: Sec. 6-2 -A mass of 40.0 grams is attached to a vertical spring with a spring constant k = 20.0 N/m and lowered slowly until the spring stops stretching. How much does the spring stretch? A) 0.00200 m B) 0.0196 m C) 0.0816 m D) 0.800 m E) 0.200 m

A tightrope walker with a mass of 60.0 kg stands at the center of a rope which was initially strung horizontally between two poles. His weight causes the rope to sag symmetrically, making an angle of 4.80° with the horizontal. What is the tension in the rope? A) 359 N B) 589 N C) 1760 N D) 2470 N E) 3520 N

A mass of 3.0 kg rests on a smooth surface inclined 34° above the horizontal. It is kept from sliding down the plane by a spring attached to a wall. The spring is aligned with the plane and has a spring constant of 120 N/m. How much does the spring stretch? A) 360 cm B) 240 cm C) 14 cm D) 24 cm E) 36 cm

FIGURE 6-10 -A 10-kg sign is held by two ropes as shown in Figure 6-10. What is the tension on rope A? A) 44 N B) 69 N C) 72 N D) 88 N E) 98 N

A 10-kg sign is held by two ropes as shown in Figure 6-10. What is the tension on rope B? A) 69 N B) 44 N C) 72 N D) 88 N E) 98 N

A 3.00-kg mass and a 5.00-kg mass hang vertically at the ends of a rope that goes over an ideal pulley. If the masses are released, what is the resulting acceleration of the masses? A) 0 m/s² B) 3.68 m/s² C) 2.45 m/s² D) 4.90 m/s² E) 6.13 m/s²

A 3.00-kg mass and a 5.00-kg mass hang vertically at the ends of a rope that goes over an ideal pulley. If the masses are released from rest, how long does it take for the 3.00-kg mass to rise by 1.00 m? A) 0.407 s B) 0.735 s C) 0.815 s D) 1.81 s E) 0.903 s

A 3.00-kg mass rests on the ground. It is attached to a string which goes vertically to and over an ideal pulley. A second mass is attached to the other end of the string and released. The 3.00-kg mass rises 50.0 cm in 1.00 s. How large was the other mass? A) 3.67 kg B) 4.29 kg C) 6.83 kg D) 7.15 kg E) 7.34 kg

FIGURE 6-11 -Refer to Figure 6-11. Block A has a mass of 3.00 kg and rests on a smooth table and is connected to block B, which has a mass of 2.00 kg, after passing over an ideal pulley, as shown. Block B is released from rest. How long does it take block B to travel 80.0 cm? A) 0.404 s B) 0.494 s C) 0.639 s D) 0.785 s E) 0.935 s

Refer to Figure 6-11. Block A has a mass of 3.00 kg and rests on a smooth table and is connected to block B, which has a mass of 2.00 kg, after passing over an ideal pulley, as shown. Block B is released from rest. What is the acceleration of the masses? A) 3.22 m/s² B) 5.10 m/s² C) 3.92 m/s² D) 6.54 m/s² E) 8.24 m/s²

Refer to Figure 6-11. Block A has a mass of 2.00 kg and rests on a rough table and is connected to block B, which has a mass of 3.00 kg, after passing over an ideal pulley, as shown. Block B is released from rest. The coefficient of kinetic friction between block A and the table is 0.300. What is the acceleration of the masses? A) 3.92 m/s² B) 0.981 m/s² C) 4.71 m/s² D) 5.89 m/s² E) 6.54 m/s²

FIGURE 6-12 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.0 kg and can slide along a smooth plane inclined 30° to the horizontal. What is the mass of block B if the system is in equilibrium? A) 1.5 kg B) 3.0 kg C) 2.6 kg D) 3.5 kg E) 6.0 kg

Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a smooth plane inclined 30.0° to the horizontal. Block B has a mass of 2.00 kg. What is the acceleration of mass B? A) 0.981 m/s² downward B) 0.981 m/s² upward C) 1.86 m/s² downward D) 1.86 m/s² upward E) 0 m/s²

Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of kinetic friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the acceleration of the blocks? A) 0.392 m/s² B) 1.96 m/s² C) 3.12 m/s² D) 5.35 m/s² E) 0 m/s²

Answer: A Diff: 3 Var: 1 Page Ref: Sec. 6-4 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of static friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the tension in the string? A) 22.0 N B) 22.7 N C) 26.1 N D) 24.5 N E) 27.3 N

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 3.00 kg, block B has a mass of 5.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses? A) 0.981 m/s² B) 1.86 m/s² C) 2.94 m/s² D) 4.20 m/s² E) 4.71 m/s²

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 6.00 kg, block B has a mass of 4.00 kg and block C has a mass of 3.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses? A) 0.981 m/s² B) 1.97 m/s² C) 2.74 m/s² D) 2.26 m/s² E) 0 m/s²

FIGURE 6-13 -Refer to Figure 6-13 Block A has a mass of 5.00 kg, block B has a mass of 3.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the tension in the string connecting blocks B and C? A) 13.7 N B) 20.6 N C) 25.5 N D) 34.3 N E) 38.3 N

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 5.00 kg, block B has a mass of 3.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the tension in the string connecting blocks A and B? A) 13.7 N B) 20.6 N C) 34.3 N D) 25.5 N E) 38.3 N

A 2-kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the acceleration of the ball? A) 0 m/s² B) 10 m/s² C) 20 m/s² D) 50 m/s² E) 0 m/s²

A 2-kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the magnitude of the net force on the ball? A) 0 N B) 20 N C) 40 N D) 50 N E) 100 N

FIGURE 6-14 -A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-14. The tension in the string is measured to be 0.200 N. What is the angle α? A) 11.2° B) 13.6° C) 18.7° D) 22.4° E) 24.6°

An airplane is flying with constant speed of 300 m/s along a horizontal circle with a radius of 15,000 m. If the lift force of the air on the wings is perpendicular to the wings, at what angle relative to the horizontal should the wings be banked? A) 15.1° B) 22.2° C) 31.5° D) 37.7° E) 63.0°

A 1000-kg car is picking up speed as it goes around a horizontal curve whose radius is 100 m. The coefficient of static friction between the tires and the road is 0.350. At what speed will the car begin to skid sideways? A) 9.25 m/s B) 23.6 m/s C) 34.3 m/s D) 35.0 m/s E) 18.5 m/s

A car moving at 10.0 m/s encounters a bump that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump? A) 200 N B) 389 N C) 789 N D) 489 N E) 589 N

A car moving at 10.0 m/s encounters a depression in the road that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the bottom of the depression? A) 200 N B) 389 N C) 789 N D) 489 N E) 589 N

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle with a radius of 600 m. At the bottom of the dive, the speed of the airplane is 150 m/s. What is the apparent weight of the 70.0-kg pilot at that point? A) 3310 N B) 686 N C) 2630 N D) 489 N E) 1370 N

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.00 times his true weight? A) 1740 m B) 1490 m C) 2240 m D) 228 m E) 41.7 m

In order to simulate weightlessness for astronauts in training, they are flown in a vertical circle. If the passengers are to experience weightlessness, how fast should an airplane be moving at the top of a vertical circle with a radius of 2.50 km? A) 157 m/s B) 314 m/s C) 78.5 m/s D) 255 m/s E) 510 m/s

A 600-kg car is going around a banked curve with a radius of 110 m at a speed of 24.5 m/s. What is the appropriate banking angle so that the car stays on its path without the assistance of friction? A) 29.1° B) 13.5° C) 33.8° D) 56.2° E) 60.9°

FIGURE 6-15 -A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-15. It moves in a horizontal circle with a constant speed of 1.50 m/s. What is the angle α? A) 10.8° B) 13.5° C) 17.7° D) 24.6° E) 49.2°

FIGURE 6-15 -A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-15. The angle α is measured to be 18.0°. What is the speed of the mass? A) 0.545 m/s B) 1.95 m/s C) 3.82 m/s D) 1.18 m/s E) 1.09 m/s

In a carnival ride, passengers stand with their backs against the wall of a cylinder. The cylinder is set into rotation and the floor is lowered away from the passengers, but they remain stuck against the wall of the cylinder. For a cylinder with a 2.0-m radius, what is the minimum speed that the passengers can have for this to happen if the coefficient of static friction between the passengers and the wall is 0.25? A) 8.9 m/s B) 2.3 m/s C) 3.0 m/s D) 4.9 m/s E) It depends on the mass of the passengers.

A 1000-kg car is moving at 30.0 m/s around a horizontal curve whose radius is 100 m. What is the magnitude of the frictional force required to keep the car from sliding? A) 9000 N B) 9810 N C) 300 N D) 900 N E) 3000 N

A 600-kg car is going around a curve with a radius of 120 m that is banked at an angle of 20° with a speed of 24.5 m/s. What is the minimum coefficient of static friction required for the car not to skid? A) 0.12 B) 0.24 C) 0.36 D) 0.48 E) 0.60

A 600-kg car is going around a curve with a radius of 120 m that is banked at an angle of 25.0° with a speed of 30.0 m/s. The coefficient of static friction between the car and the road is 0.300. What is the force exerted by friction on the car? A) 1590 N B) 3430 N C) 7240 N D) 7820 N E) 795 N

A 600-kg car is going over a curve with a radius of 120 m that is banked at an angle of 25° with a speed of 30.0 m/s. The coefficient of static friction between the car and the road is 0.30. What is the normal force exerted by the road on the car? A) 1590 N B) 3430 N C) 3620 N D) 7240 N E) 5330 N