NEET Exam Model Paper 11

Draw the free body diagram of block and platform. As M>>m,the acceleration of the platform,a=

µmg

M

can be taken as zero and hence its velocity remains constant as 4m/s. Acceleration of the block is,ablock.ground=µg=2

m

s2

towards right
Let velocity of block wrt ground at time t be v (towards right), then v=2t
Solve the question w.r.t platform frame of reference.

→

a

block.platform=2m/s2  (towards right)

→

v

block,platform=(2t−4)m/s (towards right)
Initial velocity of block wrt platform is 4 m/s towards left.
Let s be the required distance, then