A car having a mass of $1000\, kg$ is moving at a speed of $30\, metres/sec$. Brakes are applied to bring the car to rest. If the frictional force between the tyres and the road surface is $5000$ newtons, the car will come to rest in ........ $\sec$
$5$
$10$
$12$
$6$
A block of mass $40 \,kg$ slides over a surface, when a mass of $4 \,kg$ is suspended through an inextensible massless string passing over frictionless pulley as shown below. The coefficient of kinetic friction between the surface and block is $0.02$. The acceleration of block is ............ $ms ^{-2}$ (Given $g =10 \,ms ^{-2}$.)
A conveyor belt is moving at a constant speed of $2\, m s^{-1}$. A box is gently dropped on it. The coefficient of friction between them is $\mu = 0.5.$ The distance that the box will move relative to belt before coming to rest on it, taking $g = 10\, m s^{-2},$ is ........... $m$
A horizontal force of $129.4 \,N $ is applied on a $10\, kg$ block which rests on a horizontal surface. If the coefficient of friction is $0.3$, the acceleration should be ....... $m/s^2$
A bag is gently dropped on a conveyor belt moving at a speed of $2\,m / s$. The coefficient of friction between the conveyor belt and bag is $0.4$ Initially, the bag slips on the belt before it stops due to friction. The distance travelled by the bag on the belt during slipping motion is $.....m$ [Take $g=10\,m / s ^{-2}$ ]
It is difficult to move a cycle with brakes on because