6.4 Gravity and Freefall

Which would hit the ground first if dropped from the same height in a vacuum—a feather or a metal bolt?

• the feather

• the metal bolt

• They would hit the ground at the same time.

• They would be suspended in a vacuum.

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If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by

• its rate depends on its initial speed

• about 15 m/s

• about 10 m/s

• about 5 m/s

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Which object would fall with greater acceleration in a vacuum - leaf or pebble?

• The leaf

• The pebble

• Difficult to determine without more information

• Both accelerate at the same rate

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If you throw a ball straight up, what is its velocity at the highest point?

• 9.81 m/s²

• 0.0 m/s²

• 9.81 m/s

• 0.0 m/s

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The standard acceleration due to gravity (or standard acceleration of free fall), is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is defined by standard as:

• 9.8 m/s.

• 9.8 m.

• 9.8 m/s².

• 9.8 s.

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What happens to the velocity of a ball as it is dropped off a cliff?

• It decreases at a uniform rate

• It increases at a uniform rate

• It is constant

• It increases at a non-uniform rate

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When an object is accelerating due to the force of gravity and no other force it is:

• changing direction

• motionless

• in free fall

• at terminal speed

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Acceleration due to gravity is

• 9.8 m/s on Earth

• signified by the letter g

• a downward acceleration

• all of the above

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A ball is dropped from the roof of a tall building it reaches the ground in 3 seconds. What is its velocity upon impact? Use v=gt

• 9.8 m/s

• 19.6 m/s

• 29.4 m/s

• 30 m/s

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If a rocket sled starts from rest, how far does it go if it accelerates at 45 m/s² for 3.0 s?

• 15 m

• 135 m

• 5.0 m

• 202.5 m

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