Answer: 91.94 kg
Explanation: Supoose Al's mass is m. The combined mass is 168kg, so Jo's mass is 168 - m.
The Law of Conservation of Momentum states that when two objects collide, the total momentum of both objects before the collision is the same as the total momentum of both objects after the collision.
At the beginning, Al and Jo are united without movement, so their initial momentum is zero.
After the release of their hands, Al goes in one direction and Jo moves to the opposite direction. Suppose the direction Al is moving is positive. Conservation of momentum will be

where
index i referes to initial momentum
index f to final momentum
index 1 refers to Al
index 2 to Jo
Calculating:
![m(0.91)-[(168-m)(1.1)]=0](https://tex.z-dn.net/?f=m%280.91%29-%5B%28168-m%29%281.1%29%5D%3D0)


m = 91.94
Al has a mass of 91.94 kg.
Her total distance was 200 meters, since she ran 100 meters west and the same 100 meters back. This gives an average speed of 200 m / 40 s = 5 m/s.
However, her displacement was 0, since she ended at the same place she began, therefore, her average velocity is 0 / 40 s = 0.
The kinetic energy for a large vehicle is different from that of a smaller vehicle, assuming that the vehicles are travelling at the same speed and stopping the same distance. This is because for a larger vehicle the kinetic energy is higher, as the mass for a larger vehicle, is more than the smaller vehicle.
Answer:
B. temperature of the objects
Radiation can carry thermal energy.