There is a top view of a door of width l being closed by a force f pointed to the

FL/2

Explanation:

Torque = force x perpendicular distance or

Perpendicular force x distance

Here component of force perpendicular to door

=

=

Distance is breadth of the door = L

So torque =

D

Explanation:

First, we know that the acceleration is defined as the ratio of change of the velocity.

This means that, if we have a change in the velocity, then we also have acceleration.

And by Newton's second law we know that:

F = m*a

Force equals mass times acceleration.

So if we have acceleration different than zero, then we should also have force different than zero.

So we must have a nonzero net force acting on it.

The correct option is D