Question

Question in picture.

Answer 1

Hello!

The answer is: A. 19.3 joules

Why?

Since it's an elastic collision, the kinetic energy after and before the collision will be the same.

Kinetic energy can be calculated using the following equation:

`KE=(1)/(2)mv^(2)`

Where:

`KE=KineticEnergy\\m=mass\\v=velocity`

So,

First object, (going to the right):

`m=7.20kg\\v=2(m)/(s)`

`KE_(1)=(1)/(2)*7.20Kg*(2(m)/(s))^(2)=14.4Joules`

Second object:, (going to the left):

`m=5.75kg\\v=-1.30(m)/(s)`

`KE_(2)=(1)/(2)*5.75kg*(-1.30(m)/(s))^(2)=4.86Joules`

Remember,

`1Joule=1Kg.(m^(2))/(s^(2) )`

Hence,

The total kinetic energy after the collision will be:

`T=KE_(1)+KE_(2)=14.4Joules+4.86joules=19.26joules=19.3joules`

The total kinetic energy after the collision is 19.3 joules (rounded to the nearest tenth)

Have a nice day!