A block of 00kg is placed on a truck . The coefficient a static friction betwqeen the body and the truck is 0.2 the truck suddenly decreases its speed form 90km/hr to 36 km/hr in 5 seconds then

Options

A. The block does not move
B. the block slips forward and hits sthe driver's cabin
C. block shift backward
D. nothing can be saidn about the block

Answer

B

Explanation

The force of static friction ` = mumg, = 0.2 xx 100 xx 10 = 200 N`
Deceleration = (90 km/hr - 36km/hr)/5s ` = (25 m//s - 10m//s )//5s = 3m//s^(2)`
Force on the mass = 100 kg `xx 3m//s^(2) = 300` N
This is greater than the force due to static friction. Therefore due to pseudo force, the block of mass m will go forward and hit the driver.s cabin.