If the object doesn't move you have done no work.
Answer:
a. 8p
Explanation:
We are given that
Radius of hollow sphere , R1=R
Density of hollow sphere=
After compress
Radius of hollow sphere, R2=R/2
We have to find density of the compressed sphere.
We know that


Therefore,
Volume of sphere=
Using the formula



Hence, the density of the compressed sphere=
Option a is correct.
Ke = (1/2)mv²
m = 100kg, v = 10 km/s = 10*1000 = 10000m/s
Ke = (1/2)*100*10000
Ke = 500000 Joules