Forces

Which of the following is considered a contact force?

• bird to ground
• a force between two magnets
• airplane to ground
• friction between an object and air

What is the tendency of an object to resist a change in its motion?

• Inertia
• Push
• Pull
• Gravity

Which one of Newton's laws explains the following: a chair will not slide across the floor unless a force pushes the chair?

• Newton's 1st law
• Newton's 2nd law
• Newton's 3rd law
• None of the above

Which of the following is a force that acts at a distance?

• a book that rests on a desk
• a basketball being passed to a teammate
• an airplace experiencing turbulance as it moves thru the air
• a magnet pushed away with brought near another magnet

Why is the magnetic force considered to be an action-at-a distance force?

• They can be near one another to exert a force.
• They push each other apart.
• They don't have to touch one another to exert a force.
• The smaller they are, the less force they have.

What kind of force is friction?

• noncontact
• contact
• gravity
• push and pull

A box that has 100N to the left is on the floor and a person is pushing it at 150N to the right.  What is the net force?

• 250N
• 100N
• 50N
• 150N

Ted has to dumbells.  One has a mass of 3kg and the other a mass of 6kg. She pushes each with a force of 50N. How does the acceleration of the two balls compare?

• They accelerate the same.
• 3kg accelerates at half the rate as 6kg.
• 3kg accelerates twice as much as 6kg.
• 3kg accelerates 4x as much as 6kg.

A large box is on the floor and it's moving to the right with a net force of 100N.  A man is pushing it to the left with a net force of 70N. What is the net force?

• 100N
• 70N
• 170N
• 30N

A car has a net force of 200N to the right and some kids are pushing it to the right with 175N.  What is the net force?

• 200N
• 175N
• 25N
• 375N