Question

A car that experiences no frictional force is started and caused to move. For the car to continue in that motion, the gas pedal would have to be used:
at all times
infrequently
intermittently
not at all


A spacecraft is traveling in space far from any planets or stars. How much force is required to maintain the spacecraft's speed?
1/2 the mass of the spacecraft
1/4 the mass of the spacecraft
none
twice the mass of the spacecraft

Answer 1

the first one is D. there will be nothing to stop it in the first place. the second one is C. in space, nothing can stop a moving object.

Answer 2

1) Answer D not at all

The car is not experiencing any frictional force so that implies that there is no force acting on the car once it starts motion. So, according law of inertia, the car will continue to move and no other force is required.

Friction force is the resistance force that opposes the motion of any object. It arises due to the contact of surfaces.

2) Answer C none

There is no force on any spaceship moving far from any planet. So, according to law of inertia the spacecraft will continue to move at same speed.

Law of inertia states that any object keeps in the state of motion or rest unless a non zero external force is applied on it.