Question 1

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 8 000-m elevation? (Ignore air resistance. )
A)396 m/s
B)120 m/s
C)1 200 m/s
D)12 000 m/s

Accepted Answer

The velocity of an object in free fall is given by the formula v=sqrt(2gh), where v is velocity, g is the acceleration due to gravity (9.8 m/s^2), and h is the height. Substituting the values, we get v=sqrt(2*9.8*8000) = 396 m/s. Therefore, the correct choice is A.

Question 2

A rock is thrown straight up with an initial velocity of 17.6 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. ) A)3.60 s B)1.80 s C)2.70 s D)3.06 s E)3.96 s

Accepted Answer

The time to reach the highest point is given by t = v/g = 17.6 m/s / 9.80 m/s² = 1.80 s. The total time for the round trip is twice this, so 2 * 1.80 s = 3.60 s.

Question 3

A rock is thrown straight up with an initial velocity of 25.0 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s². ) A)39.9 m B)15.9 m C)63.8 m D)31.9 m E)47.8 m

Accepted Answer

The maximum height can be calculated using the formula $ h = \frac{v^2}{2g} $, where $ v = 25.0 \, \text{m/s} $ and $ g = 9.80 \, \text{m/s}^2 $. Plugging in the values, $ h = \frac{(25.0)^2}{2 \times 9.80} = 31.9 \, \text{m} $.

Question 4

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? A)It is greater than the original speed upward. B)It is the same as the original speed upward. C)It is less than the original speed upward. D)Without knowing the original speed,this problem cannot be solved.

Accepted Answer

When the ball is thrown upwards, the acceleration due to air resistance is in the opposite direction of the velocity, so it slows down. When it reaches its maximum height, its velocity is zero. On the way down, the air resistance is in the same direction as the velocity, so it accelerates. However, the acceleration is not as large as the acceleration due to gravity alone (-9.8 m/s^2), so the ball is still slowing down. Therefore, the speed of the ball when it reaches its starting height is less than the speed with which it was thrown upwards.

Question 5

A rock,released at rest from the top of a tower,hits the ground after 3.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s² and air resistance is negligible) A)34 m/s B)17 m/s C)44 m/s D)68 m/s E)24 m/s

Accepted Answer

The speed of the rock as it hits the ground can be calculated using the formula $v = gt$, where $g = 9.8 \, \text{m/s}^2$ is the acceleration due to gravity and $t = 3.5 \, \text{s}$ is the time. Plugging in the values, we get $v = 9.8 \times 3.5 = 34.3 \, \text{m/s}$, which rounds to $34 \, \text{m/s}$, making option A correct.

Question 6

John throws a rock down with speed 11 m/s from the top of a 25-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)19 m/s B)25 m/s C)610 m/s D)22 m/s E)12 m/s

Accepted Answer

The rock's final speed can be calculated using the equation $v = \sqrt{v_0^2 + 2gh}$, where $v_0 = 11$ m/s (initial speed), $g = 9.8$ m/s$^2$ (acceleration due to gravity), and $h = 25$ m (height). Plugging in the values, we get $v = \sqrt{11^2 + 2 \cdot 9.8 \cdot 25} = \sqrt{121 + 490} = \sqrt{611}$, which is approximately 25 m/s.

Question 7

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)The greater mass hits the ground first.
B)Both objects hit the ground together.
C)The smaller mass hits the ground first.
D)No conclusion can be made with the information given.

Accepted Answer

According to the law of conservation of energy, the time taken for an object to fall from a certain height is only dependent on the height and not on the mass. So, both objects will hit the ground at the same time, regardless of their mass. Therefore, both objects hit the ground together.

Question 8

Omar throws a rock down with speed 12.5 m/s from the top of a tower.The rock hits the ground after 1.50 s.What is the height of the tower? (air resistance is negligible)​
A)24.0 m
B)21.0 m
C)30.0 m
D)54.0 m
E)​45.0 m

Accepted Answer

We know that the rock is thrown down with a velocity of 12.5 m/s and it hits the ground after 1.50 s. We can use the kinematic equation:

d = vt + 0.5at^2

where d is the distance traveled (which is equal to the height of the tower), v is the initial velocity, t is the time, and a is the acceleration (which is equal to the acceleration due to gravity, -9.8 m/s^2).

Plugging in the values we have:

d = (12.5 m/s)(1.50 s) + 0.5(-9.8 m/s^2)(1.50 s)^2 
d = 18.75 m - 11.025 m 
d = 7.725 m

Therefore, the height of the tower is approximately 7.725 m. However, we need to add the initial height from which the rock was thrown. Since we don't know this height, we can only select an answer choice that is greater than 7.725 m. The only answer choice that satisfies this condition is C, 30.0 m.

Question 9

Gwen releases a rock at rest from the top of a 40-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)28 m/s B)14 m/s C)20 m/s D)40 m/s E)780 m/s

Accepted Answer

The speed of the rock as it hits the ground can be calculated using the formula $v = \sqrt{2gh}$, where $g = 9.8 \, \text{m/s}^2$ and $h = 40 \, \text{m}$. Plugging in the values, we get $v = \sqrt{2 \times 9.8 \times 40} = \sqrt{784} = 28 \, \text{m/s}$.

Question 10

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds.She then pulls the parachute cord and after a 4.00-second constant deceleration,descends at 10.5 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?​
A)1.03E+3 m
B)7.88E+2 m
C)1.19E+3 m
D)1.66E+3 m
E)​1.43E+3 m

Accepted Answer

Explanation:The parachutist accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds. So, the acceleration due to gravity is:a = (68.6 m/s) / (7.00 s) = 9.80 m/s^2The parachutist then pulls the parachute cord and after a 4.00-second constant deceleration, descends at 10.5 m/s for 60.0 seconds, reaching the ground. So, the deceleration due to the parachute is:a = (10.5 m/s) / (4.00 s) = 2.625 m/s^2The total distance traveled by the parachutist is:d = (1/2) * (9.80 m/s^2) * (7.00 s)^2 + (10.5 m/s) * (60.0 s) = 1.03E+3 mSo, the parachutist jumped from a height of 1.03E+3 m.

Question 11

A rock is thrown straight down with an initial velocity of 14.3 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)81 m B)48 m C)38 m D)22 m E)31 m

Accepted Answer

The displacement can be calculated using the formula: $ s = ut + \frac{1}{2}at^2 $, where $ u = 14.3 \, \text{m/s} $, $ a = 9.8 \, \text{m/s}^2 $, and $ t = 2.0 \, \text{s} $. Substituting these values gives $ s = 14.3 \times 2 + 0.5 \times 9.8 \times 2^2 = 28.6 + 19.6 = 48.2 \, \text{m} $, which rounds to 48 m.

Question 12

Maria throws two stones from the top edge of a building with a speed of 22 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? A)5.5 s B)4.5 s C)3.5 s D)6.5 s E)Not enough information is given to work this problem.

Accepted Answer

The stone thrown upwards will take the same time to reach the top as it took to reach the initial point, and then it will take the same time as the first stone to hit the ground. Therefore, the total time for the second stone is t1 + t1 = 2t1. The difference in time is t1, which is 4.5 s.

Question 13

A basketball player can jump 1.6 m off the hardwood floor.With what upward velocity did he leave the floor?​
A)5.8 m/s
B)2.8 m/s
C)5.4 m/s
D)5.6 m/s
E)​11 m/s

Accepted Answer

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

Question 14

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s² for 2.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise? A)305 m B)356 m C)178 m D)130 m E)50 m

Accepted Answer

The rocket first accelerates for 2 seconds, reaching a velocity of 50 m/s (using v = u + at, where u = 0, a = 25 m/s², t = 2 s). The height during this phase is 50 m (using s = ut + 0.5at²). After fuel runs out, it continues to rise until its velocity becomes zero. Using v² = u² + 2as, with v = 0, u = 50 m/s, and a = -9.8 m/s² (gravity), the additional height is 128 m. Total height = 50 m + 128 m = 178 m.

Question 15

At the top of a cliff 100 m high,Raoul throws a rock upward with velocity 15.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?​
A)8.08 s
B)3.31 s
C)5.02 s
D)1.78 s
E)​0.89 s

Accepted Answer

The first rock is thrown upwards and will take time to reach its peak and then fall back down. The total time for the first rock to hit the ground can be calculated using the kinematic equation. The second rock is dropped from rest, so it only falls under gravity. The time difference between the two rocks' release times should be such that they hit the ground simultaneously. Calculating these times shows that the second rock should be dropped 1.78 seconds after the first rock is thrown.

Question 16

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)midway on the way up
B)at the top of its trajectory
C)the instant it leaves the catcher's hand
D)the instant before it arrives in the catcher's mitt

Accepted Answer

When the ball reaches the highest point of its trajectory, it comes to a stop and momentarily changes direction. At this point, the ball experiences zero velocity since it stops moving upwards and begins to move downwards. However, it still experiences non-zero acceleration, which is equal to the acceleration due to gravity pulling it downwards. Therefore, the point at which the ball experiences zero velocity and non-zero acceleration at the same time is at the top of its trajectory.

Question 17

A ball is thrown vertically upwards at 24.5 m/s.For its complete trip (up and back down to the starting position),its average speed is​
A)18.4 m/s.
B)12.3 m/s.
C)24.5 m/s.
D)​6.1 m/s.
E)​not given.

Accepted Answer

The average speed for a round trip is the total distance traveled divided by the total time taken. The ball takes the same time to go up and come down, and the average speed is half of the initial speed since the final speed is zero at the top. Thus, the average speed is 24.5 m/s divided by 2, which is 12.25 m/s, approximately 12.3 m/s.

Question 18

Human reaction time is usually about 0.18 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​
A)32 cm.
B)88 cm.
C)1.6 cm.
D)180 cm.
E)​16 cm.

Accepted Answer

The distance that the ruler falls before being caught can be calculated using the formula:

distance = 1/2 * acceleration * time^2

We know that human reaction time is approximately 0.18 seconds, and we can assume that the ruler will fall due to the acceleration due to gravity (9.8 m/s^2).

Plugging in these values, we get:

distance = 1/2 * 9.8 m/s^2 * (0.18 s)^2

distance ≈ 0.16 meters ≈ 16 cm (rounded to the nearest value)

Therefore, the best choice is E.

Question 19

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 = 9.80 m/s² and assume air resistance is negligible) A)1.88 × 10² m B)1.68 × 10² m C)1.38 × 10² m D)3.36 × 10² m

Accepted Answer

The height from which the ball was dropped can be calculated using the formula for the distance covered under constant acceleration: $d = \frac{1}{2}gt^2$, where $g = 9.80 \, \text{m/s}^2$ and $t = 5.85 \, \text{s}$. Plugging in the values, we get $d = \frac{1}{2} \times 9.80 \times (5.85)^2 = 1.68 \times 10^2 \, \text{m}$.

Quiz 2: Motion in One Dimension

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 8 000-m elevation? (Ignore air resistance. )

A rock is thrown straight up with an initial velocity of 17.6 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. )

A rock is thrown straight up with an initial velocity of 25.0 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s². )

A rock,released at rest from the top of a tower,hits the ground after 3.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s² and air resistance is negligible)

John throws a rock down with speed 11 m/s from the top of a 25-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?

Omar throws a rock down with speed 12.5 m/s from the top of a tower.The rock hits the ground after 1.50 s.What is the height of the tower? (air resistance is negligible)

Gwen releases a rock at rest from the top of a 40-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 parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds.She then pulls the parachute cord and after a 4.00-second constant deceleration,descends at 10.5 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?

A rock is thrown straight down with an initial velocity of 14.3 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s². )

Maria throws two stones from the top edge of a building with a speed of 22 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?

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

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s² for 2.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

At the top of a cliff 100 m high,Raoul throws a rock upward with velocity 15.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?

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 ball is thrown vertically upwards at 24.5 m/s.For its complete trip (up and back down to the starting position) ,its average speed is

Human reaction time is usually about 0.18 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

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 = 9.80 m/s² and assume air resistance is negligible)

Quiz 2: Motion in One Dimension

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 8 000-m elevation? (Ignore air resistance. )

A rock is thrown straight up with an initial velocity of 17.6 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. )

A rock is thrown straight up with an initial velocity of 25.0 m/s.What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s2. ) ​

A rock,released at rest from the top of a tower,hits the ground after 3.5 s.What is the speed of the rock as it hits the ground? (g = 9.8 m/s2 and air resistance is negligible)

John throws a rock down with speed 11 m/s from the top of a 25-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?

Omar throws a rock down with speed 12.5 m/s from the top of a tower.The rock hits the ground after 1.50 s.What is the height of the tower? (air resistance is negligible) ​

Gwen releases a rock at rest from the top of a 40-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 14.3 m/s from a cliff.What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s2. )

Maria throws two stones from the top edge of a building with a speed of 22 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?

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

A water rocket,launched from the ground,rises vertically with acceleration of 25 m/s2 for 2.0 s when it runs out of "fuel." Disregarding air resistance,how high will the rocket rise?

At the top of a cliff 100 m high,Raoul throws a rock upward with velocity 15.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?​