An apple (mass = 0.25 kg) on a string 1 m in length is whirled above a student's head in a circle. The apple has a tangential speed of 12 m/s. What is the magnitude of the centripetal force on the apple?

36N

Explanation:

Given parameters:

Mass of apple  = 0.25kg

length of string  = 1m

tangential speed  = 12m/s

Unknown:

magnitude of centripetal force = ?

Solution:

The centripetal force keeps a body moving along a circular path.

It is mathematically derived using the expression below;

      F =

F is the centripetal force

m is the mass

v is the tangential speed

r is the radius

  Now insert the parameters and solve;

     F =  = 36N

the reason is because the moon has some form of gravity, and that gravity pulls the ocean tides.