Mechanical Engineering - Engineering Mechanics - Discussion

Discussion Forum : Engineering Mechanics - Section 1 (Q.No. 3)
3.
Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the ball with velocity v is made to struck the second ball. Both the balls after impact will move with a velocity
v
v/2
v/4
v/8
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
70 comments Page 3 of 7.

Sumeet said:   1 decade ago
Law of conservation of momentum.

When one ball hits second then the first ill stop & its momentum is transfer to other with the half of the velocity of first ball.

That's why answer = V/2.

Akif said:   5 years ago
In pool tables, though they aren't perfectly elastic, there can be a few results. So, we can assume for a situation where both the balls have the same velocity v/2 would be their velocity.
(1)

Tom said:   1 decade ago
The first ball will be at rest and the second will have a velocity v unless the collision angle is not zero, then in a certain angle of collision the two balls will have the same velocity.

AJEESH said:   7 years ago
This is considered as inelastic collision so both will move in same velocity, V/2, If the collision was in the vacuum, ie perfectly elastic collision, V1F will be 0 and V2F will be V.

Sakthivel said:   8 years ago
Conservation of momentum

Consider
U-initial velocity
V-final velocity
m1u1+m2u2=m1v1+m2v2
m(u1+0)=m1(v1+v2)
u1=v1+v2

Therefore finial velocity equally distributed

So u=2v.
V=u/2.

Suraj said:   8 years ago
@ALL.

It is the fact is it is a perfectly elastic collision so no kinetic energy losses. So the velocity of the 1st body will transfer to next body. And the answer will be V.

MITHUN KUMAR BISWAS said:   7 years ago
I think it would be v/√2.

If the second body before struck were in rest. Must answer should be v/√2. (kinetic energy should be equal before and after collision).

Vikas.g said:   1 decade ago
Velocity of first moving ball is v after impact its velocity becomes half therefor every action the is equal and opposite reaction so velocity of 2nd ball is also v/2.

Santhosh.M.R said:   1 decade ago
Two balls have same mass and elastic property.

So e = 1,

Momentum before impact = momentum after impact.

mv+m*0 = mv1+mv1 {after impact v1 = v2}.

Hence, v1 = v/2.

Sohan said:   9 years ago
After impact, the ball 1 will come into rest and 2 will move with velocity we.

What you guys are saying that happens only if the collision is perfectly plastic?


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