The blocks shown in figure (9-E19) have equal masses. The surface of A is smooth but that of B has a friction coefficient of 0.10 with the floor. Block A is moving
at a speed of 10 m/s towards B which is kept at rest. Find the distance travelled by B if (a) the collision is perfectly elastic and (b) the collision is perfectly inelastic. Take g = 10 m/s2.
Given that B has a friction coefficient of 0.10 with the floor.
Both the blocks have equal mass m.
Block A is moving at a speed of 10 m/s (u1=10 m/s) towards B which is kept at rest (u2=0 m/s).
Let v1 and v2 are velocities of block A and B after collision.
{a} If the collision is perfectly elastic
According to conservation of momentum
_________ (1)
Again,
__________ (2)
Subtracting equation (2) from (1)
The deceleration of B is
Putting work energy principle
Where h is the distance travelled by B
{b} If the collision is perfectly inelastic
Let the final velocity of both the blocks A and B is v.
Then, according to law of conservation of momentum
The two blocks will move together sticking to each other.
Therefore, putting work energy principle
Where s is the distance travelled by B.