Question

Portion AB of the wedge shown in figure is rough and BC is smooth. A solid cylinder rolls without slipping from A to B. If AB = BC, then ratio of translational kinetic energy to rotational kinetic energy, when the cylinder reaches point

C is –

• A. 3/5
• B. 5
• C. 7/5
• D. 8/3

Answer 1

Answer: (B)

5

Answer 2

K = bK_T

or K_T + K_R = bK_T

K_R = (b – 1)K_T Þ K_R = $\frac { 1 } { 2 }$ K_T

At point B : K_T + K_R = mg × h

\ K_R = $\frac { \mathrm { mgh } } { 3 }$

At point C : K_T + $\frac { \mathrm { mgh } } { 3 }$ = mg × 2h

K_T = $\frac { 5 \mathrm { mgh } } { 3 }$

\ = 5