Question

A block of mass m is resting on a wedge of angle q as shown in the figure. With what minimum acceleration a should the wedge move so that the mass m falls freely ?

• A. g
• B. g cosq
• C. g cot q
• D. g tan q

Answer 1

Answer: (C)

g cot q

Answer 2

$\overrightarrow { \mathrm { a } } _ { \mathrm { w } }$ = acceleration of wedge w.r.t. ground

$\overrightarrow { \mathrm { a } } _ { \mathrm { bw } }$ = acceleration of block w.r.t. wedge

$\vec { a } _ { b }$ = acceleration of block w.r.t. ground