Billy is trying to shine a laser off a mirror at the end of a basketball court into Sam's eyes to distract him (Billy is evil). Sam is at a 38 degree reflection angle from the mirror. At what angle does Billy need to shine the laser at the mirror to get it in Sam's eyes.​

When we have a plane interface, the angle of incidence of the ray is the same as the angle of reflection.

In this case, we have a mirror (we assume that it is plane) and we know that we need to have an angle of reflection equal to 38° in order to reach Sam.

Then the angle of incidence of the ray must also be exactly 38°.

Then Billy needs to shine his laser at an angle of 38° at the mirror.

(where the angle is measured between the normal line to the surface of the mirror and the incident ray)

we need to know the time interval during which the force acts. impulse of force = momentum change

a.   mass number from atomic number