Q. A 54 kg person escapes from a burning building by jumping from a window 25 m above a catching net. Assuming that air resistance exerts a 95 N force on the person during the fall, determine the person's velocity just before hitting the net.
Q. Estimate the force between a proton and an electron at the Bohr radius of 0.5Å (1 Å=10-10 m). The magnitude of the charge of an electron, as well as a proton, is 1.6·10-19 C.