A cyclist is moving to the right at a constant speed. when he applies brakes what will happen?

a -net force will be to left
b- net force will be to right
c- acting net force will be zero
d -inertia will stop him

When a cyclist applies brakes, several forces come into play:

1. Frictional force: When the brakes are engaged, brake pads press against the surface of the wheel, resulting in a frictional force acting in the opposite direction to the motion of the cyclist.

2. Inertia: Inertia is the tendency of an object to resist changes in its state of motion. As the cyclist applied brakes, the inertia of the cyclist and the bicycle will tend to keep them moving in the same direction.

Considering these forces, the net force on the cyclist will be the vector sum of the forces acting on them. In this case, the net force will be directed to the left.

Therefore, the correct answer is:
a) The net force will be to the left.