If a projectile is fired straight up from the earth’s surface, what would happen if the total mechanical energy (kinetic plus potential) is (a) less than zero, and (b) greater than zero? In each case, ignore air resistance and the gravitational effects of the sun, the moon, and the other planets.

Solution Step 1 of 3 The total mechanical energy of the body is equal to the sum of kinetic energy and potential energy. E=KE+PE Where kinetic energy is due to the vertue of the motion of the body and it is given by, KE= mv 2 2 Potential energy is the energy possessed due to vertue of the position of the body and is G m M given by, PE= - R Hence total energy, E= 1 mv - G m M ………….1 2 R