3. Physics Practice Questions - Chapter 3

3000 m/s

15) If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be

the same

16) Drop a rock from a 5-m height and it accelerates at 10 m/s2 and strikes the ground 1 s later. Drop the same rock from a height of 2.5 m and its acceleration of fall is

greater than the second before

10) If an object falling freely downward were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be

slow down the acceleration of free fall

1) Galileo's use of inclined planes allowed him to effectively

100 m/s

11) Ten seconds after starting from rest, an object falling freely downward will have a speed of about

continuously change by the same amount each second

12) If an object falls with constant acceleration, the velocity of the object must

6 m/s

19) A car accelerates from rest at 2 meters per second per second. What is its speed 3 seconds after the car starts moving?

speed

2) Which of the following is not a vector quantity?

the same as the speed it had when thrown upwards

20) A ball is thrown upwards and caught when it comes back down. Neglecting air resistance, its speed when caught is

zero

21) An object travels 8 meters in the first second of travel, 8 meters again during the second second of travel, and 8 meters again during the third second. Its acceleration in meters per second per second is

60 m/s

22) At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed is about

40 m/s

23) At one instant an object in free fall is moving upward at 50 meters per second. One second later its speed is about

acceleration

24) Disregarding air resistance, objects fall with constant

less than the speed it had when thrown upwards

25) A ball is thrown upwards and caught when it comes back down. In the presence of air resistance, the speed with which it is caught is

1.25 m

26) Starting from rest, the distance a freely-falling object will fall in 0.5 seconds is about

5 m/s

27) One half second after starting from rest, a freely-falling object will have a speed of about

100 m/s

28) An object falls freely from rest on a planet where the acceleration due to gravity is 20 meters per second squared. After 5 seconds, the object will have a speed of

250 m

29) An object falls freely from rest on a planet where the acceleration due to gravity is 20 meters per second squared. In the first 5 seconds it falls a distance of

90 km/h

3) An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is

10 m/s

30) An apple falls from a tree and hits the ground 5 meters below. It hits the ground with a speed of about

about 180 m

31) It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?

9.8 meters per second per second

32) If you drop an object, it will accelerate downward at a rate of 9.8 meters per second per second. If you instead throw it downwards, its acceleration (in the absence of air resistance) will be

increasing

33) In each second of fall, the distance a freely falling object will fall is

1 second

34) If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about

2 seconds

35) If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

get farther apart

36) Consider drops of water that leak from a dripping faucet. As the drops fall they

10 m/s

37) Disregarding air drag, how fast must you toss a ball straight up in order for it to take 2 seconds to return to the level from which you tossed it?

15 seconds

38) A car accelerates at 2 meters per second per second. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30 m/s?

4

39) A car accelerates from rest for 5 seconds until it reaches a speed of 20 m/s. What is the car's acceleration in meters per second per second?

distance and acceleration

4) The two measurements necessary for calculating average speed are

4.0

40) Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration in meters per second per second?

velocity is zero and its acceleration is about 10 meters per second per second

41) When a rock thrown straight upwards gets to the exact top of its path, its

each bullet is 9.8 meters per second per second

42) A bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, the acceleration of

(100 - 4.9) m

43) The muzzle velocity of a certain gun is 100 m/s. Neglecting air resistance, at the end of one second a bullet fired straight up into the air will have traveled a distance of

9.8

44) A bullet is fired straight down from the top of a high cliff. Neglecting air resistance, the acceleration of the bullet in meters per second per second is

is the same for each bullet

45) A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water

neither - they will both hit with the same speed

46) Someone standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed will be

30 m/s

49) A pot falls from a ledge and hits the ground 45 m below. The speed with which it hits the ground is about

20 km/h

5) The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is

1.2 m

50) The vertical height attained by a basketball player who achieves a hang time of a full 1 s is about

4.9 m/s

51) A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, one second later the rock's speed is

14.7 m/s

52) A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, two seconds later the rock's speed is

9.8 m

53) A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

zero

6) What is the acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds?

velocity increases

7) As an object freely falls downward, its

zero newtons

8) A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

40 m/s

9) If an object falling freely downward were somehow equipped with a speedometer on a planet where the acceleration due to gravity is 40 meters per second per second, then its speed reading would increase each second by

directed downward

17) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

none of these (acceleration is zero and velocity is zero)

18) While a car travels around a circular track at constant speed its

10 seconds

48) A ball is thrown 125 meters upward and then falls the same distance back to Earth. Neglecting air resistance, its total time in the air is about

at the same time as the lighter object

13) A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground

6 km/h s

14) If a car increases its velocity from zero to 60 km/h in 10 seconds, its acceleration is

about 50 m/s

47) A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds?