A small block with mass 0.0425 kg slides in a vertical circle of radius 0.525 m on the inside of a circular track. During one of the revolutions of the block, when the block is at the bottom of its path, point A, the magnitude of the normal force exerted on the block by the track has magnitude 4.05 N. In this same revolution, when the block reaches the top of its path, point B, the magnitude of the normal force exerted on the block has magnitude 0.660 N. Required:
How much work was done on the block by friction during the motion of the block from point A to point B?

Explanation:

From the question we are told that

Mass of block

Radius of circle

Force  of track

Normal Force on block

Generally the equation for Velocity of block is mathematically Given by the law of conservation of energy

For initial velocity

0.660 = 0.0425 x u^2/0.525 - 0.0425 x 9.8

Generally the equation for work done is mathematically Given by

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.