FOUR USES OF CONCAVE MIRROR:Satellite dishes,headlights of a car, telescopes used for astronomical studies, and shaving mirrors because of there curved and reflective surface.
FIVE USES OF LENSES: Camera lens ,microscopes ,magnifying glass,eyeglasses,projector
Answer:
C
Explanation:
A and B are not true and D is a disadvantage
Answer:
The height is 3.1m
Explanation:
Here we have a conservation of energy problem, we have a conversion form eslastic potencial energy to gravitational potencial energy, so:

then we have only gravitational potencial energy when the ball is at its maximun height.

because all the energy was transformed Eg=Ee

searching the web, the mass of a ping pong ball is 2.7 gr in average. so:

A. because as the merry-go-round spins the child accelerates towards the center of the merry-go-round at a uniform rate.