for work to be done a force must be exerted on a system parallel to the direction of mostion

Question

physical science

 

Answer 1

At least some component of the force must be in the same direction (i.e. parallel to) as the direction of motion, otherwise the force does no work.  If an applied force is perpendicular to the direction of motion, it does no work on the system.  If the force is not perpendicular to the direction of motion, then only the component of the force that is parallel to the direction of motion produces work on the system.

Answer 2

False.  You can push an object at an angle.  For example.  You can push a box to the left on an incline, but the box will move in the path parallel to that incline.

 

If the direction of the applied force moves in a horizontal line, then on the incline, the box will move at a non-zero slope.