Question

Superman must stop a 110-km/h train in 160 meters to keep it from hitting a stalled car on the tracks. The train's mass is 3.6 × 10⁵ kg.

a)

Determine the force that must be exerted on the train.

Express your answer to two significant figures and include the appropriate units. Enter positive value if the direction of the force is in the direction of the initial velocity and negative value if the direction of the force is in the direction opposite to the initial velocity.

b)

Compare the magnitudes of the force exerted on the train and the weight of the train (give as %).

c)

How much force does the train exert on Superman?

Express your answer to two significant figures and include the appropriate units. Enter positive value if the direction of the force is in the direction of the initial velocity and negative value if the direction of the force is in the direction opposite to the initial velocity.

Answer 1

Hi,

Hope you are doing well.

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PART (a):

Given that:

Initial velocity of the train, u = 110 km/h = 110 x 0.277778 m/s = 30.5556 m/s

Final velocity of the train, v = 0 m/s

Distance, d = 160 m

Therefore acceleration of the train is given by:

Also, We have, Mass of train, m = 3.6 × 10⁵ kg

Therefore, Force exerted on train is given by:

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PART (b):

Weight of the train is given by:

Therefore, magnitude ratio of weight and force exerted is given by:

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PART (c):

According to Newton's third law of motion, The train exerts a equal and opposite reaction:

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