What do you mean? I'm confused... You need to put the rest of the question
Answer:
Two equal and opposite parallel forces not acting along the same line, form a couple. A couple is always needed to produce the rotation.
For example, turning a key in a lock and turning a steering wheel.
Answer:
Light waves slow down as they travel from gas to solid.
Explanation:
The speed of light is often quoted with reference to a vacuum. Light travels fastest in a vacuum and in a gas.
When light travels through other media such as solids or liquids, the speed of light is decreased due to absorption and scattering of photons by molecules as well as remissions.
Hence the speed of light decreases from gas to solid.
Answer:
Work done = (1/2)[(Gmm_e)/(R_e)]
Explanation:
I've attached the explanations below.
Answer:
Explanation:
The rate of change in volume is proportional to the surface area:
dV/dt = kA
Integrating:
V = kAt + C
At t=0, V = s, so:
s = kA(0) + C
C = s
Therefore:
V = kAt + s