d. An object thrown vertically upwards reaches a height of 500 m. What was its initial velocity? How long will the object take to come back to the earth? Assume g = 10 m/s^{2 }

the final velocity is zero. We know the position is 500 and acceleration is 10

Let the initial velocity = u

final velocity = v

v= 0 m/s

s = 500 m

\(2gs=v^2-u^2\)

\(u^2= 2(10)500\) --{square root of negative }

\(u=100m/s\)

v = u + at

0 = 100 - 10 t

t = 10 s

Since it took 10 secs to go up it would take tens secs to go down thus giving us a total travel time of 20 secs.

Answer is 100 m/s 20 s