Balanced and Unbalanced Forces*

A rocket is traveling through the atmosphere at a constant velocity. Which of the following is true?

• The rocket's engine is producing an unbalanced force that keeps the rocket in the air.

• All of the forces acting on the rocket are balanced.

• The rocket exerts a greater force on its exhaust gases than the exhaust gases exert on the rocket.

• The rocket is moving, so some net force must be acting on it.

Tags

NGSS.MS-PS2-2

The units for Force are:

• Newtons

• Joules

• m/s

• kg

Student A and B are standing on a skateboard. Student A pushes gently on Student B to start her moving. Student B starts moving away from Student A. What will happen to Student A and why?

• Student A will not move, because no forces are acting on her.

• Student A will move toward Student B, because the same force is acting on both of them.

• Student A will immediately stop moving because of friction.

• Student A will move away from Student B, because an equal and opposite force pushes on her.

Tags

NGSS.MS-PS2-1

How is an object’s mass related to the force needed to accelerate the object?

• Mass determines the direction of the force needed.

• Mass determines the type of force needed.

• The greater the mass, the greater the force needed.

• The smaller the mass, the greater the force needed.

Tags

NGSS.MS-PS2-2

Use the picture to answer the following question about a game of tug of war on field day:

• The forces are balanced, so the rope does not move.

• The forces are unbalanced and the rope moves to the left.

• The forces are unbalanced and the rope moves to the right.

• The forces are unbalanced and the rope does not move.

Tags

NGSS.3-PS2-1

The full shopping cart has a mass of 75 kg and an empty one has a mass of 20kg. How much force would you need to accelerate the empty cart?

• We would need the same amount of force.

• We would need less force.

• We would need more force.

• We would not need force at all.

Tags

NGSS.MS-PS2-2

An object at rest will stay at rest until a force makes it move, is known as the Law of ________________.

• Inertia

• Friction

• Gravity

• Velocity

Which statement is a valid description and explanation of the guy’s motion based on evidence from the diagram.

• The fridge’s force is balanced due to the overall forces of gravity and friction being less than then the force of the push.

• The fridge’s force is unbalanced due to amount of push not equaling the amount of gravity.

• The fridge’s force is balanced due to the amount force exerted by the freezer and friction thus equaling to the force of push.

• The fridge’s force is unbalanced due to the larger amount push force being exerted compared to the smaller amount of frictional force.

Tags

NGSS.MS-PS2-2

Oliver the dog doesn’t want to walk in the rain. He can make his owner pull harder on the leash to get him out the door by ___________________.

• sitting on a tile floor

• sitting on a vinyl floor

• sitting on a wood floor

• sitting on a carpeted floor

George rolled a ball down a hill. The ball stopped before it reached the bottom of the hill. Which of these is most likely the reason the ball stopped rolling?

• Mass

• Inertia

• Friction

• gravity