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?