Question

If a 1.3 kg ball is dropped from the top of a 33.7 meter building what is its potential energy before it is dropped?

B) What is the maximum velocity of the ball in problem 1 just before it hits the ground?
C) How much kinetic energy does the ball in problem 1 have after it has fallen 10 m down the building?

Answer 1

Answer:429.338 J; 25.7 m/s; 127.4 J

Step-by-step explanation:

Given

mass of ball m=1.3 kg

Height of building H=33.7 m

(a)Potential Energy before dropping
`=mgH=1.3* 9.8* 33.7=429.338\ J`

(b)Velocity Just before hitting the ground

`v=√(2gH)=√(2* 9.8* 33.7)=25.7\ m/s`

(c)After falling 10 m

Here initial velocity is zero

using
`v^2-u^2=2as`

Here,

`v=\text{final veloity}`

`u=\text{Initial velocity}`

`a=\text{acceleration due to gravity}`

`s=\text{displacement}`

Putting values

`v^2-0=2* 9.8* 10\\v=14\ m/s`

So, kinetic energy
`(mv^2)/(2)=(1.3* 196)/(2)=127.4\ J`