Three blocks with masses of 1 kg,2 kg,and 3 kg are sliding down a plane inclined at an angle $\theta$ = 25 $\circ$ .If the coefficient of kinetic friction is the same for each of the blocks,which block has the greatest acceleration along the plane?
A)They all have the same acceleration
B)the 1-kg block
C)the 2-kg block
D)the 3-kg block
E)the 2- and 3-kg blocks

Question

Quizplus · Accepted Answer

The acceleration of the blocks depends on the net force acting on them. The net force in turn depends on the gravitational force (which is proportional to the mass of the block) and the frictional force (which is proportional to the coefficient of kinetic friction and the normal force, which is proportional to the component of the gravitational force perpendicular to the plane). Since the coefficient of kinetic friction is the same for each block, and the angle of inclination and the gravitational acceleration are constant, the only factor determining the net force is the mass of the block. However, since the mass cancels out in the equation for acceleration (a = net force / mass), the acceleration will be the same for all three blocks. Therefore, the answer is A, they all have the same acceleration.

Three Blocks with Masses of 1 Kg,2 Kg,and 3 Kg θ\thetaθ

Three Blocks with Masses of 1 Kg,2 Kg,and 3 Kg $\theta$