An apple falls from a tree. it hits the ground at a speed of about 8 m/s . what is the approximate height of the tree?

The motion of the apple is a free fall motion, so it is a uniformly accelerated motion. Therefore, we can use the following equation:

where

v=8 m/s is the speed of the apple when it hits the ground

u=0 is the initial speed of the apple

is the free-fall acceleration

h is the height from which the apple has fallen

Substituting data and rearranging the equation, we can find the height of the tree, h:

photocells convert light energy to electricity

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2