Freefall

A girl throws a ball straight up in the air. When does the ball accelerate down?

• On the way up.

• On the way down.

• At the top.

• All of the above

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NGSS.HS-PS2-1

NGSS.HS-PS2-4

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

• -9.8 m/s²

• -9.8 m/s

• 0 m/s²

• 0 m/s

Terry dropped a pebble from the top of his apartment building. The pebble impacted the ground after falling for 2.2 seconds. Calculate the velocity of the pebble at impact with the street below.

• -22 m/s

• -4.45 m/s

• -9.8 m/s

• -23.7 m/s

While an object is travelling upwards it's acceleration is

• upwards
• downwards

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NGSS.HS-PS2-1

When an object gets to it's maximum height it's acceleration

• changes direction
• stays upwards
• stays downwards

Tags

NGSS.HS-PS2-1

Objects that are only under the influence of gravity are considered to be  ____

• in freefall
• flying
• in freefall only if they are moving downwards

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NGSS.HS-PS2-4

A baseball dropped from the roof of a tall building takes 3.1 seconds to hit the ground. How tall is the building? [Neglect friction.]

• 15 m

• 30 m

• 48 m

• 94 m

Why is g always -9.8 m/s² on Earth?

• As objects fall down, the speed changes by 9.8m/s every second.

• As objects fall down, the speed changes by 4.9m/s every second.

• g is not always -9.8 m/s² on Earth. It changes with air resistance.

• g is experienced by all objects that fall through all space.

Which statement is true about objects in freefall?

• Objects fall a greater distance each successive second.
• Objects fall with a constant velocity.
• Objects fall with the same distance each successive second.
• Heavier objects fall faster than light objects.

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

A freely falling object starts from rest, after falling for 15s it will have a speed of about...

• 750m/s
• 15m/s
• 150m/s
• 75m/s

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4