Egg cell , sperm cell , embryo

Using the equation of motion:

h = ut - 0.5gt²,

g is -ve for a rising body, g ≈ 10 m/s², t = 4s, u = 39.2m/s

Note that in this problem we are neglecting the height of the student.

h = ut - 0.5gt²,

h = 39.2*4<span> - 0.5*10*4² Use a calculator

</span>

h = 76.8 m

The building is 76.8 m tall.

A snowball picks up speed as it rolls down the mountain.<em>** (D)**</em>

Since the description includes acceleration ("picks up speed"), we know that the forces on the snowball must be unbalanced.

The answers is it Must be tested