When no forces act on moving objects their paths are normally 

• straight lines

• circles

• ellipses

• all of the above

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

• equal to its weight

• equal to its weight divided by its mass

• equal to its mass times its weight

• none of the above

When no forces act on moving objects their paths are normally 

• straight lines

• circles

• ellipses

• all of the above

If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in

• a curved path

• an outward spiral path

• an inward spiral path

• a straight line path

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

• follow a circular path

• slow down

• follow a straight-line path

• stop

Which concept is being illustrated when a tablecloth is quickly yanked beneath dishes resting on a table?

• equilibrium

• friction

• support force

• inertia

When you flick a card from beneath a coin that hardly moves, you're illustrating

• inertia

• equilibrium

• support force

• friction

A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is

• zero

• less than 30 m/s but more than zero

• about 30 m/s

• more than 30 m/s

If your automobile runs out of fuel while driving, the engine stops. You don't come to an abrupt stop due to

• inertia

• gravity

• resistance

• the principle of continuation

When a rocket ship gaining speed in outer space runs out of fuel, it

•  gains speed for a short time, then slows down to a constant velocity.

  
  

• gains speed for a short time, slows down, and eventually stops.

  
  

• no longer gains speed.