Answer: Hope this Helps...
Explanation:
Force may be defined as the cause of motion and deformation. When a force is applied to an object, the object either moves or changes shape or both. In most cases, it is not possible to detect the deformation by naked eyes at the molecular or atomic level. Deformation occurs no matter how small.
For example, a car moving along a straight and horizontal highway, experiences an engine force Fe, while being opposed by an overall frictional force, Ff ( road friction as well as air resistance). If the car is moving to the right and to the right is taken to be the positive direction, then Fe acts to the right and Ff acts to the left. The net force is ΣF = Fe - Ff .
If a conductor wire is heated, its resistance decreases and conductivity increases.
The answer is; refraction.
When waves, including light, pass through two media with different densities, the waves bend at the transition between the two media due to differences in speed and wavelength. Convex lenses bend (refract) light and concentrate it at one point called the focal point.
There may be alternate and/or parallel universes outside of ours, but we cannot make sure. Since "space" is always expanding and never-ending, they may not be. It depends on how you look at the world and the facts and opinions of the world.
Work done = change in PE = mgh = 60*10*4 = 2400 J
