Question

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/s² 

Answer 1

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