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Re: A Puzzler
you have to make some assumptions in any problem like this.
The obvious ones are that there is no friction in the wheels and that the road and wheels can move at any speed
Think of a car trying to drive up an icy hill to get an idea - the friction between the wheels and the road is reduced - eventually you can get to a stage where you can spin the wheels as fast as you like but the car is still going to slide down the hill. Now imagine you had a rocket engine on top of the car and you flicked a switch to engage that - it wouldn't matter about the wheels and whether they spun or not. You could flick the car into reverse, but the rocket thrust would overcome both gravity and any traction you might get from the wheels spinning.
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