Question

A stone thrown from ground level returns to the same level 4 s after. With what speed was the stone thrown? Take g=10ms−2

Answer 1

Time of Ascend = Time of Descend

Answer 2

so..it Takes.2 s To Reach the Topmost Point

Answer 3

As u Know Velocity @ TopMost Point is0

V = u + at

0 = u - gt

u = gt

= 2* 10 =20m/s

Answer 4

time (t) = 2s
final velocity (v) = 0 m/s
g = - acceleration due to gravity (a) = -10m/s^2
therefore initial velocity (u) = ?
(v - u)/t = a
therefore, u = v - at
u = 0 - ((-10)*2)
u = - (-20)
u = 20 m/s