A molecules in a gas container hits the wall with speed 200m`//`s at an angle `30^(@)` with the normal, and reboudns with the same speed. Is momentum conserved in the collision ? Is the collision elastic or inelastic ?

Explanation

We know that momentum is conserved in all collisions, elastic as well as inelastic. Let us now check if K.E. is conserved or not.
As the wall is too heavy, the recoiling molecule produces no velocity in the wall, figure.
If m is mass of the gas molecule and M is mass of wall, then total K.E. after collision.
`E_(2)=(1)/(2)m(200)^(2)+(1)/(2)M(0)^(2)=2xx10^(4)mJ`
which is the K.E. of the molecule before collision. `[E_(1)=(1)/(2)m(200)^(2)=2xx10^(4)mJ]`