Question

Find the speed at which Superman (mass=76.0 kg) must fly into a train (mass = 19969 kg) traveling at 65.0 km/hr to stop it.

Running into the train at that speed would severely damage both train and passengers. Calculate the minimum time Superman must take to stop the train, if the passengers experience an average horizontal force of 0.540 their own weight.

How far does the train then travel while being slowed to a stop?

Answer 1

a, speed = 70 km/h x (17026/79) =15086 km/h b, v=u +at v=0, a=-0.5 g = -4.9 m/s^2 u=19.4 m/s t = 3.96 s c, v^2 = u^2 + 2 as as above, 19.4^2 = 2 *0.5 *g *s s = 19.4^2/9.8 = 38.6m

Hope it helps :)