Q1. A lightbulb emits a spherical wave. If the intensity of the emitted light is 1.2 W/m2 at a distance of 2.5 m from the bulb, what is the intensity at the distance of 4.8 m?
Q2. A 18.0 kg block is dragged over a rough, horizontal surface by a constant force of 77.6 N acting at an angle of 35? above the horizontal. The block is displaced 10.8 m, and the coefficient of kinetic friction is 0.149.
The acceleration of gravity is 9.8 m/s2. If the block was at first at rest, find out its final speed.