Physics Chapter 4
When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration
is 10 m/s/s
one possible unit of speed is
kilometers per minute
a unit of velocity is
meter per second
a unit of acceleration is
meters per second squared
If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first?
neither- they will both reach the bottom at the same time
Speed is
the distance covered per unit time
acceleration is best defined as
the rate at which velocity itself changes
A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be
the same speed it had when thrown upwards
When a vehicle moves around a corner at constant speed
the vehicle accelerates
Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of
5 m
A car starts from rest and after 7 seconds it is moving at 42 m/s. What is the car's average acceleration?
6 m/s/s
velocity differs from speed in that velocity
has direction
How much time does it take for a car with acceleration of 8 m/s/s to go from 62 m/s to 147 m/s?
11 s
Starting from rest, a car undergoes constant acceleration of 12 m/s/s. How far does the car travel in 2 seconds?
12 m
A ball is dropped from rest from a height of 38 m. It reaches the ground 2.8 seconds later. What is the average speed of the ball?
14 m/s
A younger runner gets a 12 m head start in a race. If the runner's speed is 3.8 m/s, how far is the runner from the starting line after 49 seconds?
198 m
In a vacuum, a marble starts from rest and falls 32 m. How long does this take?
2.5 s
A ball is thrown straight down at 6 m/s. How long will it take for the rock to reach a velocity of 32 m/s?
2.6 s
A jet on an aircraft carrier can be launched from rest to 40 m/s in 2 seconds. What is the acceleration of the aircraft?
20 m/s/s
A ski jumper starts from rest and accelerates down a ramp at 3.1 m/s/s for 5.6 seconds. What is the final speed of the ski jumper?
21.6 m/s
A bicycle is traveling at 10 m/s on a flat road. As it reaches a hill, it starts accelerating, eventually reaching 36 m/s. What is its average speed on the hill?
23 m/s
What speed must you toss a ball straight up to have it come back to you in 7 seconds?
35 m/s
An apple falls for 3.6 seconds before hitting the ground. How fast is the apple falling at the instant it hits the ground?
36 m/s
A freely falling object starts from rest. After falling for 3.8 seconds, it will have a speed of about
38 m/s
A pencil lies on your desk. If the Earth is moving around the sun at a speed of 30 km/s, how fast is the pencil moving relative to the desk? How fast is the pencil moving relative to the sun?
0 km/s; 30 km/s
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s
A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is
0 m/s/s
What is the average acceleration of a car that goes from 49 kph to 93 kph in 4 seconds?
11 km/hr/s
Suppose you take a trip that covers 240 km and takes 3 hours to make. Your average speed is
80 km/h
If a projectile is fired straight up at a speed of 45 m/s, the total time to return to its starting point is about
9 seconds
Suppose an object is in free fall. Each second the object falls
a larger distance than in the second before
A ball is thrown straight up at 40 m/s. Half way to its peak, the acceleration of the ball is
about 10 m/s/s
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by
about 10 m/s/s
In the absence of air resistance, objects fall at constant
acceleration
acceleration is defined as the CHANGE in
velocity divided by the time interval
As an object falls freely in a vacuum, its
velocity increases
a ball is thrown in the air. At the peak of its flight
velocity is zero and acceleration is nonzero
Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. Which of the following is true?
you and the car are accelerating
