9. Calculate the horizontal force that must be applied to a 1-kg puck to make it accelerate on a horizontal
friction-free air table with the same acceleration it
would have if it were dropped and fell freely?

answer; equivalent to a one(1) horsepower motor;

f is prop to m1xm2 double m1 double force

answer: the potential energy decreases from 379 j to 243 j

explanation:

for the law of conservation of energy, the total energy in a system must be conserved. the total energy of the system is given by the sum of kinetic (k) and potential (u) energy:

e = k + u

the total energy is e=675 j, and this does not change.

initially, the kinetic energy is k=296 j, so the potential energy is

at the end, the kinetic energy is k=432 j, so the potential energy is

so, we see that the potential energy has decreased from 379 j to 243 j.