Question 1

A ball of relatively low density is thrown upwards.Because of air resistance the acceleration while traveling upwards is −10.8 m/s².On its trip downward the resistance is in the opposite direction,and the resulting acceleration is −8.8 m/s².When the ball reaches the level from which it was thrown,how does its speed compare to that with which it was thrown?

Accepted Answer

The ball experiences air resistance while traveling upward, so it does not reach the same height from where it was thrown. Therefore, its initial speed cannot be equal to its final speed. As the acceleration downward is less than the acceleration upward, the ball travels downward with a higher speed than upward. Hence, the ball's speed at the level from which it was thrown would be less than the original speed upward.

Question 2

Omar throws a rock down with speed 10 m/s from the top of a tower.The rock hits the ground after 1 s.What is the height of the tower? (air resistance is negligible)
​

Accepted Answer

The answer of Omar throws a rock down with speed...

Question 3

A ball is thrown vertically upwards at 19.6 m/s.For its complete trip (up and back down to the starting position),its average speed is:
​

Accepted Answer

The ball will follow a projectile motion, reaching its maximum height when its vertical velocity becomes zero and then falling back to the starting position with the same initial velocity. The time to reach the maximum height is given by t=V₀/g, where V₀ is the initial vertical velocity and g is the acceleration due to gravity. Thus, t=19.6/9.8=2 seconds.
The maximum height reached by the ball is given by h=V₀² /2g=19.6² / (2 x 9.8) =19.6 meters.
The time to complete the round trip (up and back down) is t_total=2t=4 seconds, since the motion is symmetrical. Therefore, the total displacement of the ball is zero, and the average speed is simply the total distance traveled divided by the time taken, which is 2h/t_total = 39.2/4=9.8 m/s. Hence, the answer is (B) 9.8 m/s.

Question 4

Maria throws two stones from the top edge of a building with a speed of 18 m/s.She throws one straight down and the other straight up.The first one hits the street in a time t₁.How much later is it before the second stone hits?

Accepted Answer

Since the two stones are thrown straight up and straight down, they have the same initial velocity of 18 m/s. Therefore, the time it takes for the first stone to hit the ground is equal to the time it takes for the second stone to reach the top of its ascent and then fall back down to the ground. This means that the total time it takes for the second stone to hit the ground is twice the time it took for the first stone. Using the formula h = 1/2gt^2, we can calculate that the first stone took approximately 2.6 seconds to hit the ground. Therefore, the second stone will hit the ground approximately 5.2 seconds after it was thrown. Rounded to the nearest whole number, the answer is 4 seconds, which corresponds to choice B.

Question 5

John throws a rock down with speed 15 m/s from the top of a 27-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the rock's speed just as it hits the ground?

Accepted Answer

The final speed can be calculated using the equation v^2 = u^2 + 2gh, where u is the initial speed (15 m/s), g is the acceleration due to gravity (9.8 m/s²), and h is the height (27 m). Solving gives v ≈ 27 m/s.

Question 6

Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground.If air resistance is negligible,which statement best applies?

Accepted Answer

Objects of different mass, when dropped from the same height and in the absence of air resistance, fall with the same acceleration due to gravity. Therefore, both objects will hit the ground at the same time. This is known as the principle of equivalence and was famously demonstrated by Galileo Galilei in the 16th century.

Question 7

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s² for 1.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

Accepted Answer

The answer of A water rocket,launched from the ground,rises vertically...

Question 8

A rock is thrown straight up with an initial velocity of 22.54 m/s.What time interval elapses between the rock's being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s². )

Accepted Answer

The time to reach the highest point is given by t = v/g = 22.54 m/s / 9.80 m/s² = 2.30 s. The total time for the round trip is twice this, so 2 * 2.30 s = 4.60 s.

Question 9

Gwen releases a rock at rest from the top of a 39-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the speed of the rock as it hits the ground?

Accepted Answer

The speed of the rock can be calculated using the equation v = √(2gh), where g is the acceleration due to gravity (9.8 m/s²) and h is the height (39 m). Substituting the values, v = √(2 * 9.8 * 39) = 28 m/s.

Question 10

Two students are working on the same constant acceleration problem involving a car undergoing constant acceleration,having started from rest and after a certain time having traveled a distance of 108 m.The students are to find the average velocity.Both students are required to show their work and round any intermediate answers as well as the final answer properly to 3 significant figures.Each rounded answer is to be used in the next step of calculation as they proceed.For the final answer,Student A uses the formula 
Getting the result 7.26 m/s,and Student B uses the formula 
Getting the result 7.29 m/s.Assuming neither student makes a mistake,which student has the better answer?

Accepted Answer

The answer of Two students are working on the same...

Question 11

Mt.Everest is more than 8 000 m high.How fast would an object be moving if it could free fall to sea level after being released from an 8000-m elevation? (Ignore air resistance. )

Accepted Answer

The velocity of an object in freefall is given by the equation V = √(2gh), where g is the acceleration due to gravity (9.8 m/s^2) and h is the initial height of the object. Plugging in the numbers, we get V = √(2 x 9.8 x 8000) = 396 m/s. Therefore, the correct answer is (A).

Question 12

A baseball catcher throws a ball vertically upward and catches it in the same spot when it returns to his mitt.At what point in the ball's path does it experience zero velocity and non-zero acceleration at the same time?

Accepted Answer

At the top of its trajectory, the ball changes direction and starts falling back down. At this point, its velocity is zero (since it has just stopped moving upward and has not yet started falling downward) and its acceleration is non-zero (since gravity is acting on the ball and pulling it downward). Therefore, the answer is B.

Question 13

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s². )

Accepted Answer

The answer of A rock is thrown straight down with...

Question 14

A basketball player can jump 1.6 m off the hardwood floor.With what upward velocity did he leave the floor?
​

Accepted Answer

The answer of A basketball player can jump 1.6 m...

Question 15

A baseball is released at rest from the top of the Washington Monument.It hits the ground after falling for 5.85 s.What was the height from which the ball was dropped? (g = 9.8 m/s² and assume air resistance is negligible)

Accepted Answer

The answer of A baseball is released at rest from...

Question 16

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 49.0 m/s in 5.00 seconds.She then pulls the parachute cord and after a 5.00-second constant deceleration,descends at 11.0 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?
​

Accepted Answer

The parachutist accelerates with gravity for 5.00 seconds, reaching a maximum velocity of 49.0 m/s. The distance traveled during this time is:```d = (1/2) * a * t^2 = (1/2) * 9.8 m/s^2 * (5.00 s)^2 = 122.5 m```The parachutist then pulls the parachute cord and decelerates at a constant rate for 5.00 seconds, reaching a velocity of 11.0 m/s. The distance traveled during this time is:```d = v * t = 11.0 m/s * 5.00 s = 55.0 m```The parachutist then descends at a constant velocity of 11.0 m/s for 60.0 seconds, reaching the ground. The distance traveled during this time is:```d = v * t = 11.0 m/s * 60.0 s = 660.0 m```The total distance traveled by the parachutist is:```d = 122.5 m + 55.0 m + 660.0 m = 837.5 m```The height from which the parachutist jumped is:```h = d + 11.0 m/s * 5.00 s = 837.5 m + 55.0 m = 933 m```Therefore, the correct answer is A: 933 m.

Question 17

A rock,released at rest from the top of a tower,hits the ground after 1.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s² and air resistance is negligible)

Accepted Answer

The answer of A rock,released at rest from the top...

Question 18

A rock is thrown straight up with an initial velocity of 24.9 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s². )

Accepted Answer

The maximum height can be calculated using the formula: $ h = \frac{v^2}{2g} $, where $ v = 24.9 \, \text{m/s} $ and $ g = 9.8 \, \text{m/s}^2 $. Plugging in the values, $ h = \frac{(24.9)^2}{2 \times 9.8} = 31.6 \, \text{m} $.

Question 19

At the top of a cliff 80 m high,Raoul throws a rock upward with velocity 11.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?
​

Accepted Answer

The first rock's motion can be described by the equation $ h = v_0t + \frac{1}{2}gt^2 $, where $ h = -80 $ m, $ v_0 = 11 $ m/s, and $ g = -9.8 $ m/s². Solving for $ t $ gives approximately 4.34 s. The second rock is dropped from rest, so its time to fall is $ t_2 = \sqrt{\frac{2h}{g}} \approx 4.34 $ s. The difference in time is 4.34 s - 3.07 s = 1.27 s.

Question 20

Human reaction time is usually about 0.24 s.If your lab partner holds a ruler between your finger and thumb and releases it without warning,how far can you expect the ruler to fall before you catch it? The nearest value is:
​

Accepted Answer

The distance fallen can be calculated using the formula for free fall: $ d = \frac{1}{2}gt^2 $, where $ g \approx 9.8 \, \text{m/s}^2 $ and $ t = 0.24 \, \text{s} $. Plugging in the values, $ d = \frac{1}{2} \times 9.8 \times (0.24)^2 \approx 0.28 \, \text{m} $, which is 28 cm.

Quiz 2: Motion in One Dimension

Omar throws a rock down with speed 10 m/s from the top of a tower.The rock hits the ground after 1 s.What is the height of the tower? (air resistance is negligible)

A ball is thrown vertically upwards at 19.6 m/s.For its complete trip (up and back down to the starting position) ,its average speed is:

Maria throws two stones from the top edge of a building with a speed of 18 m/s.She throws one straight down and the other straight up.The first one hits the street in a time t₁.How much later is it before the second stone hits?

John throws a rock down with speed 15 m/s from the top of a 27-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the rock's speed just as it hits the ground?

Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground.If air resistance is negligible,which statement best applies?

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s² for 1.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

A rock is thrown straight up with an initial velocity of 22.54 m/s.What time interval elapses between the rock's being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s². )

Gwen releases a rock at rest from the top of a 39-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the speed of the rock as it hits the ground?

Mt.Everest is more than 8 000 m high.How fast would an object be moving if it could free fall to sea level after being released from an 8000-m elevation? (Ignore air resistance. )

A baseball catcher throws a ball vertically upward and catches it in the same spot when it returns to his mitt.At what point in the ball's path does it experience zero velocity and non-zero acceleration at the same time?

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s². )

A basketball player can jump 1.6 m off the hardwood floor.With what upward velocity did he leave the floor?

A baseball is released at rest from the top of the Washington Monument.It hits the ground after falling for 5.85 s.What was the height from which the ball was dropped? (g = 9.8 m/s² and assume air resistance is negligible)

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 49.0 m/s in 5.00 seconds.She then pulls the parachute cord and after a 5.00-second constant deceleration,descends at 11.0 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?

A rock,released at rest from the top of a tower,hits the ground after 1.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s² and air resistance is negligible)

A rock is thrown straight up with an initial velocity of 24.9 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s². )

At the top of a cliff 80 m high,Raoul throws a rock upward with velocity 11.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?

Human reaction time is usually about 0.24 s.If your lab partner holds a ruler between your finger and thumb and releases it without warning,how far can you expect the ruler to fall before you catch it? The nearest value is:

Quiz 2: Motion in One Dimension

Omar throws a rock down with speed 10 m/s from the top of a tower.The rock hits the ground after 1 s.What is the height of the tower? (air resistance is negligible) ​

A ball is thrown vertically upwards at 19.6 m/s.For its complete trip (up and back down to the starting position) ,its average speed is: ​

Maria throws two stones from the top edge of a building with a speed of 18 m/s.She throws one straight down and the other straight up.The first one hits the street in a time t1.How much later is it before the second stone hits?

John throws a rock down with speed 15 m/s from the top of a 27-m tower.If g = 9.8 m/s2 and air resistance is negligible,what is the rock's speed just as it hits the ground?

Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground.If air resistance is negligible,which statement best applies?

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s2 for 1.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

A rock is thrown straight up with an initial velocity of 22.54 m/s.What time interval elapses between the rock's being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s2. ) ​

Gwen releases a rock at rest from the top of a 39-m tower.If g = 9.8 m/s2 and air resistance is negligible,what is the speed of the rock as it hits the ground? ​

Mt.Everest is more than 8 000 m high.How fast would an object be moving if it could free fall to sea level after being released from an 8000-m elevation? (Ignore air resistance. )

A baseball catcher throws a ball vertically upward and catches it in the same spot when it returns to his mitt.At what point in the ball's path does it experience zero velocity and non-zero acceleration at the same time?

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s2. )

A basketball player can jump 1.6 m off the hardwood floor.With what upward velocity did he leave the floor? ​

A baseball is released at rest from the top of the Washington Monument.It hits the ground after falling for 5.85 s.What was the height from which the ball was dropped? (g = 9.8 m/s2 and assume air resistance is negligible) ​

A rock,released at rest from the top of a tower,hits the ground after 1.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s2 and air resistance is negligible)

A rock is thrown straight up with an initial velocity of 24.9 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s2. ) ​

At the top of a cliff 80 m high,Raoul throws a rock upward with velocity 11.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff? ​

Human reaction time is usually about 0.24 s.If your lab partner holds a ruler between your finger and thumb and releases it without warning,how far can you expect the ruler to fall before you catch it? The nearest value is: ​

Omar throws a rock down with speed 10 m/s from the top of a tower.The rock hits the ground after 1 s.What is the height of the tower? (air resistance is negligible)

A ball is thrown vertically upwards at 19.6 m/s.For its complete trip (up and back down to the starting position) ,its average speed is:

Maria throws two stones from the top edge of a building with a speed of 18 m/s.She throws one straight down and the other straight up.The first one hits the street in a time t₁.How much later is it before the second stone hits?

John throws a rock down with speed 15 m/s from the top of a 27-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the rock's speed just as it hits the ground?

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s² for 1.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

A rock is thrown straight up with an initial velocity of 22.54 m/s.What time interval elapses between the rock's being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s². )

Gwen releases a rock at rest from the top of a 39-m tower.If g = 9.8 m/s² and air resistance is negligible,what is the speed of the rock as it hits the ground?

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s². )

A basketball player can jump 1.6 m off the hardwood floor.With what upward velocity did he leave the floor?

A baseball is released at rest from the top of the Washington Monument.It hits the ground after falling for 5.85 s.What was the height from which the ball was dropped? (g = 9.8 m/s² and assume air resistance is negligible)

A rock,released at rest from the top of a tower,hits the ground after 1.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s² and air resistance is negligible)

A rock is thrown straight up with an initial velocity of 24.9 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s². )

At the top of a cliff 80 m high,Raoul throws a rock upward with velocity 11.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?

Human reaction time is usually about 0.24 s.If your lab partner holds a ruler between your finger and thumb and releases it without warning,how far can you expect the ruler to fall before you catch it? The nearest value is: