A body of mass 10kg is moving with velocity 10m/sec.The work done to stop the body is :
A) 500J B)-500J C)1000J D)-1000J
How to calculate the answer?
500j
m=10kg,v=10m/s, ke=1/2×10×10×10=500
500j
The kinetic energy of a body of mass m=10kg moving at v=10m/s is
E=(1/2)mv²
After being stopped, the kinetic energy of the body has been transferred to work done (assuming no frictional loss), and has nothing left.
So we can find
Work done=loss/reduction in kinetic energy.
1000j
To calculate the work done to stop the body, we need to use the work-energy principle, which states that the work done on an object is equal to its change in kinetic energy.
The kinetic energy of an object is given by the formula:
Kinetic Energy = (1/2) * mass * velocity^2
In this case, the mass of the body is 10 kg and the initial velocity is 10 m/s. The final velocity will be 0 m/s since the body is being stopped.
So, the initial kinetic energy is:
Initial Kinetic Energy = (1/2) * 10 kg * (10 m/s)^2
= 500 J
The final kinetic energy is:
Final Kinetic Energy = (1/2) * 10 kg * (0 m/s)^2
= 0 J
The work done to stop the body is the change in kinetic energy:
Work Done = Final Kinetic Energy - Initial Kinetic Energy
= 0 J - 500 J
= -500 J
Therefore, the correct answer is B) -500J.