7th Gr Unit 2 (4-7)

Bow and Arrow: Which type of energy conversion is involved when the arrow is released? 

• 1. When the bowstring is released, gravitational energy is transformed into the kinetic energy of the arrow.

• 1. When the bowstring is released, kinetic energy is transformed into elastic energy.

• 1. When the bowstring is released, this elastic energy is transformed into the kinetic energy of the arrow.

• 1. Elastic energy is released when the bowstring is pulled back and ready.

Tags

MS-PS3-5

What determines how much elastic energy an object can have?  

• 1. The more an object can be stretched or deformed and still go back to its original shape the more elastic energy it has. 

• 1. The thicker an object the more elastic energy it has.

• 2. The greater the mass of the object the greater it's elastic potential energy.

• 1. The higher you raise a ball before letting it bounce the greater elastic energy the ball has.

Tags

MS-PS3-2

What energy conversions occur when a ball bounces?  Select all that apply.

• 1. Gravitational energy —> Kinetic energy —> Gravitational energy

• 1. As the ball drops:   Gravitational energy —> Kinetic energy 

• 1. When the ball reaches the ground: Kinetic energy —> Elastic energy —> Kinetic energy

• 1. After bouncing, the ball moves back up: Kinetic energy —> Gravitational energy

• 1. Gravitational energy —> Kinetic energy —> Elastic Energy —> Gravitational energy

Tags

MS-PS3-5

What type of energy can be used to describe anything that can be stretched or squeezed and returns to its original shape?  

• 1. Gravitational Energy

• 1. Thermal Energy

• 1. Kinetic Energy

• 1. Elastic Energy 

Tags

MS-PS3-2

What are the factors that influence the amount of elastic energy in an object? Circle all that are correct. 

• 2. stretching

• 1. compression

• 1. hardness

• 1. mass 

Tags

NGSS.MS-PS3-5

Why did the tennis ball bounce higher when bouncing from the basketball than when it was originally dropped?

• 1. The tennis ball bounced higher because it started from a higher position on the basketball.

• 1. Both the tennis ball and the basketball had increased kinetic energy when they were bounced together. 

• 1. The tennis ball bounced higher because energy was transferred to it from the basketball. The basketball then bounced lower than it did on its own.

• 1. The tennis ball bounced to the same height regardless of where it starts.

Tags

MS-PS3-5

MS-PS3-2

What causes the pendulum to slow down and eventually stop?

• 1. The pendulum slows down and eventually stops because it transfers kinetic energy to the surrounding air molecules.

• 1. The pendulum slows down and eventually stops because gravity pulls it down toward the center of the Earth.

• 1. The GE of the pendulum gets transferred to the air around the pendulum and causes it to stop.

Tags

MS-PS3-2

Why does a ball stops bouncing?

• 1. Each time a ball hits the floor the KE gets converted to GE and some is lost to gravity. The GE gets transferred to KE and then to Elastic Energy. Friction also plays a role.

• 1. The ball stops bouncing because each time it strikes the ground some of its energy is transferred to the surroundings, so less remains for the ball. This continues until none remains for the ball and then it stops.

• 1. The ball stops bouncing because each time it strikes the floor the elastic energy absorbs the shock. The KE and GE decrease over time until it slows down and stops.

Tags

MS-PS3-5

A student drops a ball from 5 feet above the ground. After bouncing once, it only reaches a maximum height of 4 feet above the ground. Why the ball did not reach its original height after bouncing once?

• 1. When the ball hits the ground, the elastic energy absorbs so much energy that there is less kinetic energy available to get it up in the air as far as it was initially.

• 1. The friction of passing through the air and hitting the floor decreases its energy so the ball is unable to bounce as high.

• 1. Some of the ball’s energy was transferred to the floor and the surrounding air so that the ball was left with less energy than it originally had. 

• 1. The material in the ball compresses and slightly flattens so it is unable to bounce as high after that.

Tags

MS-PS3-5

 When the steel balls hit the paper, into what types of energy are some of the KE converted? What evidence supports your thinking?

• 1. Some of the KE was converted to GE because the balls pushed back.

• 1. Some of the KE was converted to TE because the TE burned a hole in the paper that was between the two steel balls.

• 1. The KE was not converted because the steel balls continued to move after they hit each other.

• 1. The KE was transferred to the paper and then back to the next steel ball.

Tags

MS-PS3-2