Question 1

A 6.0 kg box is held at rest by two ropes that form 30° angles with the vertical.An external force F acts vertically downward on the box.The force exerted by each of the two ropes is denoted by T.A force diagram,showing the four forces that act on the box in equilibrium,is shown in the figure.The magnitude of force F is 410 N.The magnitude of force T is closest to:

Accepted Answer

The box is in equilibrium, so the sum of forces in both the vertical and horizontal directions must be zero. The vertical forces include the weight of the box (mg = 6.0 kg * 9.8 m/s² = 58.8 N), the external force F (410 N), and the vertical components of the tension in the ropes (2Tcos30°). Solving for T gives T = (mg + F) / (2cos30°) = (58.8 N + 410 N) / (2 * √3/2) ≈ 271 N.

Question 2

A piano mover raises a 100 kg piano at a constant rate using a frictionless pulley system,as shown in the figure.With roughly what force is the mover pulling down on the rope?

Accepted Answer

C

Question 3

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s². )

Accepted Answer

The acceleration can be calculated using the formula: a = g(sinθ - μcosθ). Substituting the given values: a = 9.8(sin39° - 0.19cos39°) ≈ 4.7 m/s².

Question 4

-Dick and Jane stand on a platform of negligible weight,as shown in the figure.Dick weighs 500 N and Jane weighs 400 N.Jane is supporting some of her weight on the end of the rope she is holding.What is the downward force she is exerting on the platform?

Accepted Answer

Jane is supporting 100 N of her weight on the rope, so she is exerting 300 N on the platform.

Question 5

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s².What is the person's apparent weight? (Use g = 9.8 m/s². )

Accepted Answer

The apparent weight is the normal force exerted by the elevator floor, which is the sum of the gravitational force and the force due to the elevator's acceleration. Apparent weight = m(g + a) = 78 kg * (9.8 m/s² + 1.8 m/s²) = 78 kg * 11.6 m/s² = 904.8 N, which rounds to 900 N.

Question 6

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface?

Accepted Answer

The correct answer is A because the mass of an object is directly proportional to the gravitational force it experiences. The greater the mass, the greater the gravitational force.

Question 7

A 80 N force is needed to slide a 50.0 kg box across a flat surface at a constant velocity.What is the coefficient of kinetic friction between the box and the floor? (Use g = 9.8 m/s². )

Accepted Answer

The coefficient of kinetic friction is given by the equation:$$f_k = \mu_k * n$$where:* $f_k$ is the force of kinetic friction* $\mu_k$ is the coefficient of kinetic friction* $n$ is the normal forceIn this problem, the force of kinetic friction is 80 N, the normal force is equal to the weight of the box, which is 50.0 kg * 9.8 m/s^2 = 490 N, and the coefficient of kinetic friction is unknown.Substituting these values into the equation, we get:$$80 N = \mu_k * 490 N$$Solving for $\mu_k$, we get:$$\mu_k = 80 N / 490 N = 0.16$$Therefore, the coefficient of kinetic friction between the box and the floor is 0.16.

Question 8

Kieran takes off down a 50 m high,10° slope on his jet-powered skis.The skis have a thrust of 280 N.The combined mass of skis and Kieran is 50kg (the fuel mass is negligible).Kieran's speed at the bottom is 40 m/s.What is the coefficient of kinetic friction of his skis on snow?

Accepted Answer

The work done by the thrust is equal to the change in kinetic energy plus the work done by friction. The work done by friction is equal to the coefficient of kinetic friction times the normal force times the distance traveled. The normal force is equal to the weight of the skier and skis minus the thrust. The distance traveled is equal to the height of the slope divided by the sine of the slope angle.$$W_f=\mu_k n d$$$$W_f=\mu_k (mg-T) \frac{h}{\sin	heta}$$$$W_f=\mu_k (50	imes9.8-280) \frac{50}{\sin10°}$$$$W_f=11760\mu_k$$$$W_f=\frac{1}{2}mv_f^2-\frac{1}{2}mv_i^2$$$$11760\mu_k=\frac{1}{2}(50)(40)^2-0$$$$11760\mu_k=40000$$$$\mu_k=0.47$$

Question 9

A skydiver reaches a "terminal velocity" of 120 km/h.If the skydiver has a mass of 59.0 kg,what is the magnitude of the upward force on the skydiver due to wind resistance? (Use g = 9.8 m/s². )

Accepted Answer

The upward force due to wind resistance equals the gravitational force at terminal velocity. The gravitational force is calculated as mass times gravity: 59.0 kg * 9.8 m/s² = 578.2 N, which rounds to 578 N.

Question 10

Jason takes off across level water on his jet-powered skis.The combined mass of Jason and skis is 75 kg (the mass of the fuel is negligible).The skis have a thrust of 200 N and a coefficient of kinetic friction on water of 0.1.Unfortunately,the skis run out of fuel after only 67 s.How far has Jason traveled when he finally coasts to a stop?

Accepted Answer

The answer of Jason takes off across level water on...

Question 11

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µs = 0.40 and µk = 0.30,respectively.The puck's initial speed is 63 m/s.What vertical height does the puck reach above its starting point?

Accepted Answer

The correct answer is A because the puck will reach a vertical height of 130 cm above its starting point. This can be calculated using the following equation:h = (v^2 * sin^2(theta)) / (2 * g * (µk * cos(theta) + sin(theta)))where:h is the vertical height reached by the puckv is the initial speed of the pucktheta is the angle of the rampg is the acceleration due to gravityµk is the coefficient of kinetic friction

Question 12

A 15 kg block is on a ramp that is inclined at 20° above the horizontal.It is connected by a string to a 19 kg mass that hangs over the top edge of the ramp.Assuming that frictional forces may be neglected,what is the magnitude of the acceleration of the 19 kg block? (See the figure. )

Accepted Answer

The answer of A 15 kg block is on a...

Question 13

A tightrope walker walks across a 30.0 m long wire tied between two poles.The center of the wire is displaced vertically downward by 1.0 m when he is halfway across.If the tension in both halves of the wire at this point is 6294 N,what is the mass of the tightrope walker? Neglect the mass of the wire.

Accepted Answer

The tension in the wire creates two equal and opposite forces. At the midpoint, the vertical component of the tension equals the weight of the walker. Using trigonometry, T*sin(θ) = mg, where θ is the angle of the wire with the horizontal. The angle can be found using tan(θ) = 1/15. Solving gives m ≈ 85 kg.

Question 14

An object at rest on an inclined plane starts to slide when the incline angle is increased to 17°.What is the coefficient of static friction between the object and the incline? (Use g = 9.8 m/s². )

Accepted Answer

The coefficient of static friction is given by the formula μs = tan θ, where θ is the angle of inclination at which the object starts to slide. Therefore, μs = tan 17° = 0.31.

Question 15

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s². )

Accepted Answer

The correct answer is A. The reading on the scale will be 676 N. This is because the scale measures the force of gravity acting on the fish, which is equal to the mass of the fish times the acceleration due to gravity. In this case, the mass of the fish is 69.0 kg and the acceleration due to gravity is 9.8 m/s^2, so the force of gravity acting on the fish is 676 N.

Question 16

Three blocks, connecting ropes, and a light frictionless pulley comprise a system, as shown. An external force P is applied downward on block A. The system accelerates at the rate of 2.5 m/sS1U1P12S1S1P0. The tension in the rope connecting block B and block C equals 60 N.
-In the figure above,the external force P is closest to:

Accepted Answer

The answer of 
Three blocks, connecting ropes, and a light...

Question 17

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s². )

Accepted Answer

The force of friction is given by:$$f_s=\mu_sn$$where:* $f_s$ is the force of friction* $\mu_s$ is the coefficient of static friction* $n$ is the normal forceThe normal force is equal to the force applied perpendicular to the surface:$$n=F\cos	heta$$where:* $F$ is the applied force* $	heta$ is the angle between the applied force and the surfaceThe maximum force of friction is equal to the coefficient of static friction times the normal force:$$f_s=\mu_sn=0.76F\cos25^\circ$$The maximum force that can be applied without moving the trunk is equal to the force of friction:$$F=f_s=0.76F\cos25^\circ$$Solving for $F$, we get:$$F=\frac{f_s}{\cos25^\circ}=\frac{0.76F}{\cos25^\circ}=0.85F$$Therefore, the maximum force that can be applied without moving the trunk is 0.85 times the applied force. The applied force is 750 N, so the maximum force that can be applied without moving the trunk is:$$F=0.85(750	ext{ N})=637.5	ext{ N}$$The mass of the trunk is equal to the force applied divided by the acceleration due to gravity:$$m=\frac{F}{g}=\frac{637.5	ext{ N}}{9.8	ext{ m/s}^2}=65	ext{ kg}$$Therefore, the most massive trunk that can be moved is 65 kg.

Question 18

Starting from rest,a 75 kg skier slides down a 17.0° slope.If the coefficient of kinetic friction between the skis and snow is 0.120 and it takes 16.9 s to get to the bottom,how long is the ski trail? (Use g = 9.8 m/s². )

Accepted Answer

The correct answer is A because the skier's acceleration is 2.45 m/s2, so the distance traveled is 248 m.

Question 19

A device has a 100 g wooden shuttle that is pulled horizontally along a square frictionless wooden rail by an elastic band.The shuttle is released when the elastic band has 6.4 N tension at a 35º angle.What is the magnitude of the initial acceleration of the shuttle? (See the figure. )

Accepted Answer

The answer of A device has a 100 g wooden...

Question 20

A 10.0 kg block on a table is connected by a string to a 63 kg mass,which is hanging over the edge of the table.Assuming that frictional forces may be neglected,what is the magnitude of acceleration of the 10.0 kg block when the other block is released? (See the figure. )

Accepted Answer

The answer of A 10.0 kg block on a table...

Quiz 5: Applying Newtons Laws

A piano mover raises a 100 kg piano at a constant rate using a frictionless pulley system,as shown in the figure.With roughly what force is the mover pulling down on the rope?

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s². )

-Dick and Jane stand on a platform of negligible weight,as shown in the figure.Dick weighs 500 N and Jane weighs 400 N.Jane is supporting some of her weight on the end of the rope she is holding.What is the downward force she is exerting on the platform?

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s².What is the person's apparent weight? (Use g = 9.8 m/s². )

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface?

A 80 N force is needed to slide a 50.0 kg box across a flat surface at a constant velocity.What is the coefficient of kinetic friction between the box and the floor? (Use g = 9.8 m/s². )

Kieran takes off down a 50 m high,10° slope on his jet-powered skis.The skis have a thrust of 280 N.The combined mass of skis and Kieran is 50kg (the fuel mass is negligible) .Kieran's speed at the bottom is 40 m/s.What is the coefficient of kinetic friction of his skis on snow?

A skydiver reaches a "terminal velocity" of 120 km/h.If the skydiver has a mass of 59.0 kg,what is the magnitude of the upward force on the skydiver due to wind resistance? (Use g = 9.8 m/s². )

A 15 kg block is on a ramp that is inclined at 20° above the horizontal.It is connected by a string to a 19 kg mass that hangs over the top edge of the ramp.Assuming that frictional forces may be neglected,what is the magnitude of the acceleration of the 19 kg block? (See the figure. )

An object at rest on an inclined plane starts to slide when the incline angle is increased to 17°.What is the coefficient of static friction between the object and the incline? (Use g = 9.8 m/s². )

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s². )

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s². )

Starting from rest,a 75 kg skier slides down a 17.0° slope.If the coefficient of kinetic friction between the skis and snow is 0.120 and it takes 16.9 s to get to the bottom,how long is the ski trail? (Use g = 9.8 m/s². )

A device has a 100 g wooden shuttle that is pulled horizontally along a square frictionless wooden rail by an elastic band.The shuttle is released when the elastic band has 6.4 N tension at a 35º angle.What is the magnitude of the initial acceleration of the shuttle? (See the figure. )

A 10.0 kg block on a table is connected by a string to a 63 kg mass,which is hanging over the edge of the table.Assuming that frictional forces may be neglected,what is the magnitude of acceleration of the 10.0 kg block when the other block is released? (See the figure. )

Quiz 5: Applying Newtons Laws

A piano mover raises a 100 kg piano at a constant rate using a frictionless pulley system,as shown in the figure.With roughly what force is the mover pulling down on the rope?

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s2. )

-Dick and Jane stand on a platform of negligible weight,as shown in the figure.Dick weighs 500 N and Jane weighs 400 N.Jane is supporting some of her weight on the end of the rope she is holding.What is the downward force she is exerting on the platform?

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s2.What is the person's apparent weight? (Use g = 9.8 m/s2. )

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface?

A 80 N force is needed to slide a 50.0 kg box across a flat surface at a constant velocity.What is the coefficient of kinetic friction between the box and the floor? (Use g = 9.8 m/s2. )

Kieran takes off down a 50 m high,10° slope on his jet-powered skis.The skis have a thrust of 280 N.The combined mass of skis and Kieran is 50kg (the fuel mass is negligible) .Kieran's speed at the bottom is 40 m/s.What is the coefficient of kinetic friction of his skis on snow?

A skydiver reaches a "terminal velocity" of 120 km/h.If the skydiver has a mass of 59.0 kg,what is the magnitude of the upward force on the skydiver due to wind resistance? (Use g = 9.8 m/s2. )

A 15 kg block is on a ramp that is inclined at 20° above the horizontal.It is connected by a string to a 19 kg mass that hangs over the top edge of the ramp.Assuming that frictional forces may be neglected,what is the magnitude of the acceleration of the 19 kg block? (See the figure. )

An object at rest on an inclined plane starts to slide when the incline angle is increased to 17°.What is the coefficient of static friction between the object and the incline? (Use g = 9.8 m/s2. )

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s2. )

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s2. )

Starting from rest,a 75 kg skier slides down a 17.0° slope.If the coefficient of kinetic friction between the skis and snow is 0.120 and it takes 16.9 s to get to the bottom,how long is the ski trail? (Use g = 9.8 m/s2. )

A device has a 100 g wooden shuttle that is pulled horizontally along a square frictionless wooden rail by an elastic band.The shuttle is released when the elastic band has 6.4 N tension at a 35º angle.What is the magnitude of the initial acceleration of the shuttle? (See the figure. )

A 10.0 kg block on a table is connected by a string to a 63 kg mass,which is hanging over the edge of the table.Assuming that frictional forces may be neglected,what is the magnitude of acceleration of the 10.0 kg block when the other block is released? (See the figure. )

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s². )

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s².What is the person's apparent weight? (Use g = 9.8 m/s². )

A 80 N force is needed to slide a 50.0 kg box across a flat surface at a constant velocity.What is the coefficient of kinetic friction between the box and the floor? (Use g = 9.8 m/s². )

A skydiver reaches a "terminal velocity" of 120 km/h.If the skydiver has a mass of 59.0 kg,what is the magnitude of the upward force on the skydiver due to wind resistance? (Use g = 9.8 m/s². )

An object at rest on an inclined plane starts to slide when the incline angle is increased to 17°.What is the coefficient of static friction between the object and the incline? (Use g = 9.8 m/s². )

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s². )

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s². )

Starting from rest,a 75 kg skier slides down a 17.0° slope.If the coefficient of kinetic friction between the skis and snow is 0.120 and it takes 16.9 s to get to the bottom,how long is the ski trail? (Use g = 9.8 m/s². )