Question

A block of mass 10 kg. is moving in x-direction
with a constant speed of 10m/sec. It is subjected
to a force F=-0.1 x joules/meter during its travel
from x=20 meters to x=30 meters. Its final kinetic
energy will be - nom
(AIIMS 2005]
(1) 475 joules (2) 450 joules
(3) 275 joules (4) 250 joules​

Answer 1

Answer:

1)475J

Explanation:

Here,

Mass of body(m)=10kg

Speed of body(v)=10m/s(const.)

Force(F)=-0.1dxJ/m

initial position(x1)=20m

Final position(x2)=30m

W=KEf - KEi

W=KEf - 1/2mv^2

F.dx=KEf - 1/2×10×(10)^2

-0.1xdx=KEf - 500

0.1 integration of x from 20 to 30 = KEf - 500

0.1/2[(30)^2-(30)^2]=KEf - 500

-25=KEf - 500

KEf = 475Joules