Force and Motion Review

Which statement about acceleration is always true?

• Both speed and direction must change for acceleration to occur.

• The unit m/s is the SI unit of acceleration.

• For objects to accelerate, they must speed up.

• Either a change in speed or a change in direction causes acceleration.

What is the relationship between the kinetic energy of an object and the mass of an object? Assume the speed is constant.

• Kinetic energy gets bigger at a faster rate than the increase of a mass of an object.

• Kinetic energy decreases as the mass of an object increases

• Kinetic energy gets bigger at the same rate as the mass of an object.

• Kinetic energy decreases at a faster rate than the increase of a mass of an object.

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NGSS.MS-PS3-1

Nicki rides her bike at a constant speed for 6 km. That part of her ride takes her 1 h. She then rides her bike at a constant speed for another 9 km. That part of her trip takes her 2 h. What is her average speed?

• 3 km/h

• 5 km/h

• 5.25 km/h

• 7.5 km/h

Nikhil bought a large plant in a planter for his mother. He took it home and pushed it around his living room until he found a good location for it near the window. After he watered the plant, he was very surprised how difficult it was to push the planter. Based on Newton’s second law, why does it become more difficult to move the planter? Choose the three statements that apply.

• Nikhil had to apply more force to produce the same acceleration.

• Increased inertia means that less force is needed to move the planter.

• If Nikhil used the same amount of force, the acceleration of the moving planter would be less after adding the water.

• With the water, the planter had more mass and more inertia.

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NGSS.MS-PS2-2

Which term describes resistance to change in motion?

• acceleration

• inertia

• net force

• velocity

A dog is pulling on a leash while walking down the sidewalk. What frame of reference would indicate that the dog is not moving?

• A nearby building

• The leash

• A tree

• The sidewalk

Pam’s family is clearing some land, and there is a large boulder sitting on top of the ground. Even with the entire family pushing on it, they cannot move it. Which type of friction exists between the boulder and the ground?

• rolling

• sliding

• fluid

• static

Daylon’s family just bought a new puppy, and Daylon decided to take him for a walk. He put the puppy in a wagon and pulled the wagon along the sidewalk. From which of these reference points does the puppy appear to be moving?

• the wagon

• the sidewalk

• the puppy's collar

• Daylon

You can find the speed on a distance-time graph by finding the _______________ of the line.

The acceleration of a baseball after its hit by a bat depends on the mass of the ball and the net force on the ball. This example best illustrates what law?

• Newton's 1st Law of Motion

• Newton's 2nd Law of Motion

• Newton's 3rd Law of Motion

• Newton's Law of Universal Gravitation

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NGSS.MS-PS2-2