Question

. A ball is thrown vertically upwards. It goes to a height of 19.6 m and then returns back to the ground. Find the : (
a. Initial velocity of the ball (
b. Total time of journey (
c. Final velocity of the ball when it strikes the ground.

Answer 1

please confirm the answer is correct or not and let me know.

Answer 2

Given:- A ball is thrown vertically upwards. It goes to a height of 19.6 m and then returns back to the ground.

To find:- the : a. Initial velocity of the ball

b. Total time of journey

c. Final velocity of the ball when it strikes the ground.

Solution:-

a. According to the question,

height s = 19.6 m

Let, initial velocity= u

as it was thrown vertically upwards

acceleration = -9.8 m/s²

and final velocity is 0 m/s²

as we know v²= u²+2as

so, 0²= u²+ 2(-9.8)(196)

or, u = 19.6 m/s

b. let the total time is 2×t= 2t

and we know v= u+at

or, 0= 19.6+(-9.8)t

or, t = 2s and 2t = 2×2s= 4s

c. And for the downward motion

u= 0 m/s

let, the final velocity is v m/s

a = 9.8 m/s

t= 2s

v=u+at = 0+(9.8)2= 19.6 m/s

So, a. Initial velocity of the ball is 19.6 m/s

b. Total time of journey is 4 seconds

c. Final velocity of the ball is 19.6 m/s when it strikes the ground