Forces and Newton's Laws

A book is lying at rest on a table.  The book will remain there at rest because:

• there is a net force but the book has too much inertia

• there are no forces acting on it at all

• there is no net force on the book

• there is a net force, but the book is too heavy to move

A hockey puck slides on ice at constant velocity.  What is the net force acting on the puck?

• more than its weight

• equal to its weight

• depends on the speed of the puck

• zero

You put your backpack on the bus seat next to you.  When the bus stops suddenly, the backpack slides forward off the seat.  Why?

• Because a net force acted on the backpack

• Because no net force acted on the backpack

• Because the backpack remained at rest

• Because gravity stopped acting on the backpack

Consider a cart on a horizontal frictionless track.  You gave the cart a push and released, what will happen to the cart?

• It will slowly come to stop

• It will continue moving with constant acceleration

• It will continue moving with constant velocity

• It will immediately come to stop

After you gave a cart a push and released, it's started moving at constant velocity. What needs to be done to get the cart continue to move with constant acceleration?

• Push the cart harder before release

• Push the cart longer before release

• Push the cart continuously

• Change the mass of the cart

A force F acts on mass m₁ giving acceleration a₁. The same force F acts on a different mass m₂ giving acceleration a₂ = 2a₁. What is the mass m₂?

While on Earth, you kick a bowling ball and hurt your foot. A year later you travel to the Moon and kick the same bowling ball with the same force on the Moon. Your foot hurts...

• the same

• more

• less

• doesn't hurt at all

What is different about the bowing ball on the Moon and on Earth?

• mass

• wheight

• size

• color

Consider two identical blocks, one resting on a flat surface, and the other resting on an incline. For which case is the normal force F_N greater?

• For case A

• For case B

• Both the same,

  F_N = mg

• Both the same,

  F_N = 0

A small car collides with a large truck. Which experiences the greater impact force?

• The car

• The track

• Both the same

• It depends on the velocity of each car