Explain why (a) a horse cannot pull a cart and run in empty space, (b) passengers are thrown forward from their seats when a speeding bus stops suddenly, (c) it is easier to pull a lawn mower than to push it, (d) a cricketer moves his hands backwards while holding a catch.

Explanation

While trying to pull a cart , a horse pushes the ground backwards with a certain force at an angle . The ground offeres an equal reaction in the opposite direction , on the horse . The forward component of this reacion is responsible for motion of the cart . In empty space , there is no reaction and hence , a horse cannot pull the cart and run .