Hi. Here's a tricky one (for me, anyway):
"A train has a mass of 5.07 x 10^6 kg and is moving at 75.5 km/hr. The engineer applies the brakes, which results in a net backward force of 1.71 x 10^6 N on the train. The brakes are held on for 26.0 s. What is the new speed of the train?"
We are applying a backward force F on a mass m which is moving with a velocity u. This will produce a deceleration a on the train.
For this, we can write, ...
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