Question

I have been reading a published article which tried to explain collisions between rigid and non-rigid bodies and it mentioned the following :

The deformation prone mass in humans has been referred to as ‘‘wobbling mass’’ and is unable to transmit impact forces as effectively as rigid mass (Gruber et al., 1998). During a collision the greater the rigidity of the impacting mass, the less elastic the collision. The less elastic a collision, the greater the momentum imparted into the target or opponent (Pain & Challis, 2002).

But I thought the more rigid a body is , the more elastic the collision, like the collision between 2 billiard balls. There is no virtually no deformation and 'kinetic energy/momentum' can be assumed conserved.

But isn't the collision between 2 rubber balls also an approximate elastic collision, which seems to contradict the billiard ball example?

So does the rigidity of an impacting mass affect the momentum transfer to the impacted mass?

Answer 1

The rigidity of an impacting mass does affect the momentum transfer to the impacted mass. Non-rigid bodies, like human bodies, are unable to transmit impact forces as effectively as rigid bodies. However, there can still be approximate elastic collisions with non-rigid bodies.

Step-by-step explanation:

In general, the rigidity of an impacting mass does affect the momentum transfer to the impacted mass. The article you mentioned is referring to the fact that non-rigid bodies, like human bodies, are unable to transmit impact forces as effectively as rigid bodies.

This is because non-rigid bodies, also known as 'wobbling mass', deform during a collision, which reduces the efficiency of momentum transfer. On the other hand, rigid bodies, like billiard balls, are able to conserve kinetic energy and momentum during a collision, resulting in a more elastic collision where there is virtually no deformation.

However, it is important to note that there can be approximate elastic collisions with non-rigid bodies as well, such as the collision between two rubber balls. Although there is deformation in this case, it is limited and the collision can still be considered elastic. This demonstrates that the rigidity of a body is not the sole factor determining the elasticity of a collision.