A block of mass M is placed on a fixed smooth inclined plane of inclination ‘A’ with the horizontal is at rest. The force exerted by the plane on the block has a magnitude:
As the object on inclined plane is at rest net force acting on the object is zero. Force applied on object by earth is Mg. Resultant of Normal reaction and friction force will cancel gravitational force. So the force applied by inclined plane on block is Mg in vertically upward direction.
Consider a car moving on a straight road with a speed of 10 ms-1. The distance at which car can be stopped is: [μ=0.5]
Friction force action on the object is f=μ.N= μ.mg
Retardation of the block is a=μ.g = 0.5× 10 =5
Using equation of motion. Stopping distance = u^2/2a=(10 × 10)/( 2* 5)=10 m
A marble block of mass 2 kg lying on ice when given a velocity of 6 ms-1 is stopped by friction in 10 s. Then the coefficient of friction is
Using equation of motion
v= u + at
⇒ 0= 6 + a ×10
⇒ a= -0.6 m/sec^2
Maximum Friction force is μN = μ mg so, a= μ.g
⇒ -0.6 = - μ. 10
⇒μ = 0.06