8th grade 1st 9 weeks (science)

A ball starts from rest. It rolls down a ramp and reaches the ground after 4 seconds. Its final velocity when it reaches the ground is 7.0 meters/second.

The initial velocity of the ball is ___ meters/second, and its acceleration is ___ meters/second²

• 0, 1.75

• 1.75, 0

• 4, 7

• 7, 4

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NGSS.MS-PS3-1

NGSS.MS-PS3-5

An airplane is flying at a constant speed in a positive direction. It slows down when it approaches the airport where it's going to land. Which term describes the slowing of the plane?

• stationary

• positive velocity

• positive acceleration

• negative acceleration

• constant velocity

Tags

NGSS.MS-PS3-5

Andrew pokes a marble, and the marble rolls down a ramp. The marble moves with speed. Which forces are acting on the marble in this situation?

When Andrew pokes the marble, he gives it ___ force

• an applied

• a tension

• a friction

• a gravitational

Tags

NGSS.MS-PS2-2

As the marble rolls down the ramp, ___ force pulls it down.

• tension

• normal

• gravitational

• pressure

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NGSS.MS-PS2-4

The movement of the marble is slowed down by gravitational forcefrictionelastic force from the ramp.

• force

• friction

• elastic

• gravity

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NGSS.MS-PS2-2

NGSS.MS-PS2-4

Kae'Shawn throws a basketball at the gym floor. The ball bounces once on the floor and comes to rest in his coach’s hands. At which point are all the forces on the basketball balanced?

• the moment the ball leaves Kae'Shawn's hand

• the moment the ball touches the floor

• when the ball is in the air

• when the ball starts falling downward before coming to rest

• the moment the ball comes to a complete rest

Tags

NGSS.MS-PS2-2

Diana accidently dropped her toy stuffed animal from the balcony of her apartment on the fourth floor. The toy hit the ground at a velocity of 16.0 meters/second. At impact, it took 2.0 seconds for the toy’s velocity to reach 0 meters/second. If the toy has a mass of 0.25 kilograms, what's the force of the impact? Use F = ma, where a= (v-u)/t.

The force of the impact is ___ newtons.

Tags

NGSS.MS-PS2-2

A motorcycle is moving at a constant velocity of 15 meters/second. Then it starts to accelerate and reaches a velocity of 24 meters/second in 3 seconds. What’s the acceleration of the motorcycle over this time? Use the equation for a.

Which sentence states Newton’s third law?

• If two objects collide, each object exerts a force in the same direction as the other

• If two objects collide, each object exerts a force equal to and in the opposite direction of the other.

• A collision between a moving object and a stationary object is elastic.

Tags

NGSS.MS-PS2-1

Marleni uses a claw hammer to remove a nail from a wall. She applies a force of 40 newtons on the hammer. The hammer applies a force of 160 newtons on the nail. The mechanical advantage of the hammer is ___.