Answer:
Explanation:
Cutting a string in half because
b is irreversible
c is a cheical and d is also a chemical change
The initial kinetic energy of the boat and its rider is

After Sam stops it, the final kinetic energy of the boat+rider is

because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:

where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.
Answer:
momentum=mass×velocity
momentum =400kg×20m/s=8000kg.m/s
A. people from the same location share the same personality type.