Chapter 12.1,12.2, 12.3 Science
Consider drops of water leaking from a water faucet. As the drops fall they
get closer together
When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration
in g; no more, no less
A ball tossed vertically upward rises, reaches its highest point, and then falls back to its straight point. During his time the acceleration of the ball is always
in the direction of motion.
When you look at the speedometer in a moving car, you can see the car's
instantaneous acceleration
A ball is thrown upwards and caught when it comes back. In the absence of air resistance, the speed of the ball when caught would be
the same as the speed it had when thrown upwards
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. It's acceleration is
0m/s2
Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of
5 m
If a projectile is fired straight up at a speed of 30 m/s, the total time to return to its starting point is about
6 seconds
A car starts from rest and after 7 seconds it is moving at 42m/s. What is the car's average acceleration?
6m/s2
A ball is thrown into the air. At the highest point, the ball has zero velocity and zero acceleration.
False
A unit of acceleration is meters per second.
False
A unit of velocity is the meter.
False
As a ball falls freely, the distance it falls each second is the same.
False
Average speed is defined as the time it takes for a trip divided by the distance
False
Unless stated otherwise, when we discuss the speeds of things, we mean with respect to the center of the universe.
False
When a car rounds a corner at a constant speed, it is acceleration is zero.
False
If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first?
Neither- they both reach the bottom at the same time.
Velocity is different from speed in that velocity is speed in a given direction.
True
The vertical height attained by a basketball plater who achieves a hang time of a full once second is about
more than 2.5 m
If a ball were equipped with a speedometer and allowed to fall freely on a planet where the acceleration due to gravity is 23 m/s, the reading on the speedometer would increase each second by
23 m/s
Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40km/h the first second and from 40km/h to 45 km/h the next second. What is the car's acceleration?
35 km/h x s
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.
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 it's path its instantaneous speed is
0 m/s
A freely falling object starts from rest. After falling for 1 second, it will have a speed of about
10 m/s
A car accelerates at 2 m/s. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20 m/s?
10 seconds
A free falling object starts from rest. After falling for 6 seconds, it will have a speed of about
60 m/s
Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is
60km/h
Acceleration is defined as
The rate at which velocity itself changes
Even though a car is slowing down, it is still accelerating in the most general definition of acceleration.
True
The rate at which distance is covered is called speed.
True
The rate at which velocity changes with time is called acceleration.
True
When we discuss the motion of something, its motion is described relative to something else.
True
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 NOT true?
Your velocity is constant.
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 the top of its path its acceleration is
about 10 m/s
If a freely falling objects were somehow equipped with a speedometer, its speed reading would increase each second by
about 15 m/s
When something falls to the ground, it accelerates. This acceleration is called the acceleration due to gravity and is symbolized by the letter g. What is the value of g on Earth's surface?
about 5 m/s
One possible unit of speed is
all of the above
Speed is
all of the above
The hang time (time one's feet are off the ground in a jump) for most athletes is
considerably more than 1 second.
Acceleration is defined as the CHANGE in
distance divided by the time interval
In the absence of air resistance, objects fall at constant
velocity
As an object falls freely in a vacuum, its
velocity increases.
