Question

A 1.8 kg book has been dropped from the top of the football stadium. Its speed is 4.8 m/s when it is 2.9 m above the ground. How high is the stadium?

Answer 1

the height of the stadium is 4 m

Step-by-step explanation:

The computation of the height of the stadium is shown below:

but before that total mechanic energy should be determined

E = PE + KE

where

PE = mgh

and, KE = 1 ÷2 mv^2

Now

E = mgh + 1 ÷2 mv^2

= (1.8) (9.8) (2.9) + 1 ÷ 2 (1.8) (4.8)^2

= 71.9J

= 72J

Now the height of the stadium is

TE = mgh

72 = (1.8) × (9.8) × h

So, h = 4 m

Hence, the height of the stadium is 4 m