SPEED, VELOCITY AND ACCELERATION

A car travels 100km. The journey takes two hours. The highest speed of the car is 80km/ h, and the lowest speed is 40km/ h. What is the average speed for the journey?

• 40km/ h

• 50km/ h

• 60km/ h

• 120km/ h

An object is released from rest and falls to Earth. During its fall, the object is affected by air resistance. The air resistance eventually reaches a constant value. Which description about successive stages of the motion of the object is correct?

• constant acceleration, then constant deceleration

• constant deceleration, then zero acceleration

• decreasing acceleration, then constant deceleration

• decreasing acceleration, then zero acceleration

Tags

NGSS.HS-PS2-1

On Earth, a ball is dropped and falls 2.0 m in a vacuum. The acceleration of the ball at 1.0 m is 10 m/s² .

What is the acceleration of the ball at 0.5 m?

• 5.0 m / s²

• 10 m / s²

• 15 m / s²

• 20 m / s²

Tags

NGSS.HS-PS2-1

An ice crystal falls vertically from a cloud. What happens to the acceleration of the ice crystal as it falls?

• It decreases because of air resistance.

• It decreases because of gravity.

• It increases because of air resistance.

• It increases because of gravity.

Tags

NGSS.MS-PS2-2

An athlete runs at a speed of 8 m / s for 10 s, and then at a speed of 6 m / s for 12s. Which calculation gives the average speed of the athlete in m / s?

A boy runs 400 m at an average speed of 4.0 m / s. He runs the first 200 m in 40 s. How long does he take to run the second 200 m?

• 60 s

• 66.7 s

• 80 s

• 140 s

An object is moving with uniform deceleration. Which statement describes its motion?

• Its rate of change of speed is decreasing.

• Its speed is constant.

• Its speed is decreasing.

• Its speed is increasing.

The velocity of an object increases from 30 m / s to 50 m / s in 5.0 seconds.

What is the average acceleration of the object?

• 0.10 m / s²

• 0.25 m / s²

• 4.0 m / s²

• 10 m / s²

Tags

NGSS.HS-PS2-1

A car travels at an average speed of 60 km / h for 15 minutes. How far does the car travel in 15 minutes?

• 4.0 km

• 15 km

• 240 km

• 900 km

A student investigates the motion of a ball rolling down a slope. The diagram shows the speed v of the ball at different times t.

Which statement describes the motion of the ball?

• The acceleration is not constant.

• The acceleration is negative.

• The speed is decreasing.

• The velocity is constant.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-1