Question

A body is dropped from 1000m height, if its potential energy is 8 x 10^8 J. What will be its velocity on reaching the ground
(a) 1410 ms
(b)141 ms
(c) 1.41 ms
(d) 9800 ms
(correct answer is b why?) ​

Answer 1

1/2m×v^2 = 8×10^8

we get mass =8×10^4

....b is the correct answer because....

by solving it we get...the value of v from my above written equation...

all the potential energy is converted to kinetic energy just before reaching the ground...

Answer 2

Answer:

b

Explanation:

If there's no air friction then

Loss if P. E = Gain in K. E

so

mgh =1/2 mv²

gh= 1/ 2v²

2gh= v²

√2hg = v

now just put the value of hight and g

✓(2 * 1000 * 10) = v

v= 141 ms-1