Explanation:
an electrical load is the part of an electrical circuit in which current is transformed into something useful. examples include a lightbulb, a resistor and a motor. a load converts electricity into heat, light or motion. put another way, the part of a circuit that connects to a well-defined output terminal is considered an electrical load.
-- You've GOT the kinetic energy of the bullet.
-- That's the amount of work that has to be done to stop it.
-- work = (avg force) x (penetration) and they just gave you the average force.
-- Did you think it would be this easy ?
Answer:
The work done against friction is 372 joules
Explanation:
It is given that,
Mass of block, m = 24 kg
Radius of the track, r = 15 m
Acceleration due to gravity, 
If the kinetic energy of the block at the bottom of the track is, 3900 J
Let P is the work done against friction. It is given by :

Here, h = r

P = 3528 J
Since it ends up with 3900 J, the work done is given by or the lost in energy will be :
W = 3900 - 3528
W = 372 joules
So, the work done against friction is 372 joules. Hence, this is the required solution.