# Question #b1c2e

##### 1 Answer

Jan 15, 2017

(b)

#### Explanation:

When disc of mass

- Potential energy
#PE=mgh# - Rotational Kinetic Energy given by
#KE_R=1/2Iomega^2 #

where moment of inertia#I=1/2mR^2# and angular velocity#omega=v/R# - Translational Kinetic energy
#KE_T=1/2mv^2#

(We have ignored friction in this statement.)

We also know that

(a) Initial energy at the top of hill when disc is at rest it has only

(b) At the bottom of hill all the

By Law of Conservation of energy

#TE_"(a)"=TE_"(b)"#

Inserting given values we get