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

(a) when horse pulls cart its feet applies difinite force certain angle on the surface on feet of the horse . Due to component of force cart comes into motion .
( b) When bus is in motion due to inertia passenger inside the bus also are in motion when the bus suddenly stop due to are thrown forward their seats .
(c )
To pull lawn mover force is applied by making angle `theta` with horizontal shown in figure vertically component of this force is mg sin `theta` due to this net force will become mg - F sin ` theta`
When machine is given push force is applied by making angle `theta` downward direction component of force in downward direction will be mg + F sin `theta` .Due to this is easy to pull lawn mover instead of pushing it.
(d ) When cricket catches ball by taking his hand in backward direction these by increase time of contact between ball and hence less force act on hand impulse of force increase.