Measuring forces

According to Newton’s Third Law, what happens when a swimmer pushes against the pool wall to propel themselves forward?

•  The wall pushes back against the swimmer with the same amount of force.

• The wall pushes back against the swimmer with twice as much force.

• The wall pushes back against the swimmer with half as much force.

• The wall does not push back against the swimmer; the force of the swimmer’s push is what propels them forward.

Tags

NGSS.MS-PS2-1

1. A box is acted upon by two forces from opposite directions. What is the net force applied to the box?

• 1. 10 N

• 20 N

• 1. 30 N

• 40 N

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Choose the answers that best describe what is happening in the image.

• The forces are balanced

• The forces are unbalanced.

• The system is stable.

• The system is unstable.

Tags

NGSS.MS-PS2-2

CHALLENGE: A person is using a pulley to pull on a bell. Calculate the net force on the bell using the measurements listed in the diagram.

• 20 N up

• 20 N down

• 80 N up

• 80 N down

Tags

NGSS.MS-PS2-2

CHALLENGE: Choose the answers that best describe the forces or system.

• The forces are balanced.

• The forces are unbalanced.

• The system is stable.

• The system is unstable

Tags

NGSS.MS-PS2-2

Two workers at a furniture store are moving a couch to another display. One worker pushes with a force of 150 N and the other pushes with a force of 180 N in the same direction.

What is the net force exerted on the couch?

• 30 N

• 1. 150 N

• 180 N

•  330 N

Tags

NGSS.MS-PS2-2

A student in gym class wants to climb the rope attached to the ceiling. They pull with a force of 80 N but do not move off the ground.

What is the net force exerted on the student?

• 0 N

• 40 N

• 80 N

• 160 N

Tags

NGSS.MS-PS2-2

A pet owner takes his dog out in the morning for exercise. The dog is happy to be out and pulls forward on his leash at a force of 100 N. The owner keeps the dog close by gently pulling backward on the leash with a force of 110 N.
Calculate the net force on the leash.

• 110 N backward

• 210 N forward

•  10 N backward

• 0 N

Tags

NGSS.MS-PS2-2

According to Newton’s Third Law, what happens when a runner pushes back against the ground to propel themselves forward?

• The ground simultaneously exerts the same amount of force on the runner.

• The ground simultaneously exerts twice as much force on the runner.

• The ground simultaneously exerts half as much force on the runner.

• The ground does not exert any force on the runner.