Question

a balt is thrown vertically upwards from the ground with a velocity 39.2 m/ s . Calculate -
(A) The maximum height to which the ball rises and
(B) The time taken to reach the highest point.

Answer 1

Intial velocity(u) = 39.2 m/s
final velocity(v) = 0
acceleration(a) = -9.8
a) using third equation of motion
2as = v^2 -u^2
2 (-9.8)(s)= (0)^2 - (39.2)^2
-19.6 s = - 1536.64
19.6s = 1536.64
s = 1536.64 / 19.6
= 78.4
so,
the maximum height covered = 78.4 m
b) let time taken be t
using acceleration formula
a= (v-u)/t
-9.8 = (0- 39.2)/t
-9.8 t = -39.2
9.8t = 39.2
t = 39.2 / 9.8
= 4
so,
the time taken was 4s to reach maximum height.