It is well known that bullets and other missiles fired at Superman simply bounce off his chest. Suppose that a gangster sprays Superman's chest with 5.6 g bullets at the rate of 110 bullets/min, and the speed of each bullet is 480 m/s. Suppose too that the bullets rebound straight back with no change in speed. What is the magnitude of the average force on Superman's chest from the stream of bullets

Relax

Respuesta :

Answer:

4.93 N

Explanation:

We know that force F = dP/dt where dP/dt = rate of change of momentum and P = momentum = mv

Now, F = dP/dt = dmv/dt = vdm/dt + mdv/dt

Now since we have 5.6 g bullets, m = 5.6 g = 0.0056 kg, dm/dt = rate of change of mass of bullet hitting superman per second = mass of one bullet × rate of change of bullet = 0.0056 kg/bullet × 110 bullets/min = 0.0056 kg/bullet × 110 bullets/min × 1 min/60 s = 0.0103 kg/s, v = speed of bullet = 480 m/s and dv/dt = 0.

So, F = vdm/dt

= 0.01027 kg/s × 480 m/s

= 4.929 kgm/s²

= 4.929 N

≅ 4.93 N

So, the average force is 4.93 N