Question

3. Object A (3 kg) moves at a speed of 8 m/s and object B (5 kg) moves at a speed of 4 m s. If
the collision between the object A and B is perfectly elastic, what is the velocity of object A
and B after the collision?​

Answer 1

Answer:

Known :

Mass of object A (m1) = 3 kg

Mass of object B (m2) = 5 kg

The speed of object A (v1) = 8 ms–1

The speed of object B (v2) = 4 ms–1

Perfectly elastic collision.

Wanted:

v1‘ and v2‘

Solution :

If both objects have the different mass and the velocity of both objects after the collision is not known yet, then the velocity after collision calculated using this equation :

Collisions – problems and solutions 1

The direction of both objects is the same so that the velocity of both objects have the same sign. If both objects move in opposite direction then one velocity has plus sign and another velocity has minus sign.

The velocity of object A (vA) after the collision :

Collisions – problems and solutions 2

The velocity of object B (vB) after the collision :

Collisions – problems and solutions 3

Velocity of object A (v1‘) after collision is 3 m/s and velocity of object B (v2‘) after collision is 7 m/s.

Explanation:

HOP IT HELPS UH !!

Answer 2

Given,

3kg object moves with 8m/s velocity

5kg object moves with 4m/s velocity.

To Find,

After elastic collision velocity of A and B.

Solution,

Here, both objects have the different mass and the velocity and velocity of both objects after the collision is not known yet, then the velocity after collision calculated using this equation,

vA=(m1-m2/m1+m2 )v1+(2m2/m1+m2)v2

vB=(2m1/m1+m2)v1+(m2-m1/m1+m2)v2

Here direction of both objects is the same so that the velocity of both objects have the same sign.

The velocity of A after collision,

vA=(3-5/3+5)8+(2×5/3+5)4

   =(-2/8)8 + (10/8)4

   =-2+5

   =3m/s

The velocity of B after collision,

vB=(2×3/3+5)8+(5-3/3+5)4

   =(6/8)8+(2/8)4

   =6+1

  =7m/s

Hence, after collision between A and B the velocity of A will be 3m/s and B will be 7m/s.