Coming to horsepower, it is the opposite of torque. It is the high-end power of a car. A horsepower is basically a unit of power; more horsepower will give your car the push to move fast.

Power is the amount of work done per time. According to the expressions below, it is clear that Power is directly proportional to acceleration.
Force, F=ma; Work, W=F.s;  Power=W/t

The experimental meaning of horsepower can be explained by taking an example. Let a car have a power of 500 hp. 1hp = 75 kg m/s, which means a body with 1hp can move a weight of 75 kg up to 1m in 1sec. So, having 500hp means the car can move (75×500)kg or 37500 weight up to 1m in 1 sec.
1hp is also the power used to 33,000lbs push/pull over 1foot in 1 minute.