8th Grade Science STAAR - Cat. 2 Review

Unbalanced force causes a change in motion; this is called __________.

• inertia

• acceleration

• velocity

• friction

If a golfer hits a golf ball with a mass of 0.08 kg and it accelerates at 1500 m/s², what was the force used to cause the ball to accelerate at this rate?

• 120 N

• 12 N

• 1200 N

• 0.12 N

The kayaker is traversing some rapids and is resisting the current by dragging the paddle. If the water has a current of 5 m/s² flowing southeast and the kayaker applies a resistance force of 3 m/s², what is going to happen to the kayak?

• The kayak will move southeast with a net force of 2 m/s².

• The kayak will move northwest with a net force of 2 m/s².

• The kayak will stay in place with no net force.

• The kayak will move southeast with a net force of 8 m/s².

A tennis player hits a tennis ball with a force of 10 N, and the ball has an air resistance force of 0.7 N. What is the net force acting on the tennis ball?

• 9.3 N

• 10.7 N

• 0.7 N

• 10 N

_______ is a measurement of the rate of change of position with respect to time.

• Acceleration

• Velocity

• Speed

• Momentum

_______ is a change of an object’s speed or direction.

• Acceleration

• Velocity

• Speed

• Momentum

_______ is a measurement of speed and direction of an object.

• Acceleration

• Velocity

• Speed

• Momentum

If the motorcycle racer is traveling at a speed of 16 m/s around the track and is going around a curve, why is the rider changing velocity if speed stays the same?

• Because the rider is accelerating.

• Because the direction of motion is changing.

• Because the speed is increasing.

• Because the speed is decreasing.

What describes the meteor's motion that passed near Earth in 2013 and was only visible with the aid of a telescope?

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Describe Newton's 1st Law of Motion.

• An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

• For every action, there is an equal and opposite reaction.

• The force exerted on an object is equal to the mass of the object multiplied by its acceleration.

• The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass.