Question

a boy throws a ball upwards and catches it back in 10s calculate the velocity with which it was thrown up

Answer 1

Answer:

50 m/s

Explanation:

Time of flight ( T ) = 10s

We know,

T=(2u/g)

Therefore,

u = (Tg/2)

= (10*10/2)

= (100/2) = 50 m/s

Hope it help

Answer 2

Question:-

A boy throws a ball upwards and catches it back in 10s calculate the velocity with which it was thrown up?

Solution:-

Given,

• A boy throws a ball upwards with a velocity and reached ground in 10sec.
• Then the time taken to reach the highest is 5sec and to reach ground is 5sec.

We have to use first equation of motion to find the initial velocity:-

g = -10 ; t = 10s ; v = 0 ; u = ?

➣ v = u + gt

➣ 0 = u + (-10)(5)

➣ 0 = u - 50

➣ $\boxed{u \: = \: 50}$

Then,

s = ?

➣ s = ut + 1/2 gt²

➣ s = 50 × 5 + 1/2 × -10 × 5 × 5

➣ s = 250 + (-5) × 5 × 5

➣ s = 250 -125

➣ $\boxed{s \: = \: 125}$

Verification:-

s = ut + 1/2 gt²

➣ 125 = 50 × 5 + 1/2 × -10 × 5 × 5

➣ 125 = 250 + (-5) × 5 × 5

➣ $\boxed{125 \: = \: 125}$

And,

➣ v = u + at

➣ 0 = 50 + (-10)(5)

➣ 0 = 50 - 50

➣ $\boxed{0 \: = \: 0}$