Question

a coin is placed on a rotating disc than what will be the change in its angular speed
justify.

Answer 1

Answer:

When the coin is just on the verge of slipping, it just overcomes the force of static friction (F

s

) . which acts as centripetal force for being that coin in the circular motion.

So we have

F

s

=mω

2

r

If we double the ω, then r will also self adjust to a new r

′

, since the static friction will remain same. We have

mω

2

r=m(2ω)

2

r

′

⇒r

′

=

4

r

cm=

4

4

cm=1 cm