Physics Unit 3

A bullet is dropped into a river from a very high bridge at the same time as another bullet is fired straight downward from a rifle. Neglecting air resistance, the acceleration just before striking the water is

the same for each bullet

The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about

1 s

Neglecting air resistance, how fast must you toss a ball straight up in order for it to take 6 seconds to return to its initial level?

30 m/s

If you throw a ball straight downward (in the absence of air resistance., after leaving your hand its acceleration is

10 m/s2

When a ball thrown straight upwards reaches the very top of its path, its acceleration is

10 m/s2

An object falls freely from rest on a planet where the acceleration due to gravity is 20 m/s2. After 5 seconds, the object will have a speed of

100 m/s

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

10m/s

If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about

180m

If a freely falling object were equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s2, then its speed reading would increase each second by

20 m/s

An object at rest near the surface of a distant planet starts to fall freely. If the acceleration there is twice that of the Earth, its speed one second later would be

20m/s

At one instant a heavy object in air is moving upward at 50 m/s. One second later its speed is approximately

40 m/s

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

5 m/s

Compared with hang time on Earth, hang time on the Moon would be

greater

The distance a freely falling bowling ball falls each second

increases

Twelve seconds after starting from rest, a freely-falling cantelope has a speed of

more than 100 m/s

The accelerations possible for a ball on an inclined plane

range from zero to g.

While an iron block near the Earth's surface is in free fall, it undergoes an increase in

speed