Question

It is well known that bullets fired at Superman simply bounce off his chest. Suppose that a gangster sprays Superman's chest with bullets of mass m = 4.0 g at a rate of R = 170 bullets/min. The speed of each bullet is v = 470 m/s. Suppose the bullets rebound with no change in speed. What is the average force exerted by the stream of bullets on Superman's chest?

Answer 1

. Solutions mass of bullet = 4 g = 0.004 kg te Rate of bullet = 170 bullets per minut Speed of each bullet v= 470 m/s F = 1/2 krizon Average force is given as | Var AP= change in momentum and AP. = mar = ml ve-vi) - mlv-(-v) - 2 mv at - Change in momentum AP = 2m v • for one bullet 2x0.00+ x 470 = 3.76 Kg.m/s Now, In one minute 170 bullets are striking Superman's chest so average momentan 170 billet is AP = 170 X 3.76 = 639.2 kg-m/s - Average Force per minute is = AP 639.2 kg-m/s 1 min = 639.2 kg-mis - 60s Fax = 10.65 kg-m/s?