The greater the force you apply to an object (say a shot) and the longer you apply this force for the greater will be the change of velocity of the object. However something else affects this change in velocity. To find out the change in velocity we must use the idea of MOMENTUM.

Momentum = mass x velocity

If we apply a certain impulse to an object we will get a certain change of momentum. The velocity change depends on the mass of the object:

Impulse = change of momentum or Ft = mv - mu

where u is the initial velocity and v the final velocity. The units of momentum are the same as those for impulse, that is Newton seconds (Ns).

For a given
momentum change you either need a large force acting for a short time or a small force acting for a long time.

Remember that momentum is a vector quantity like velocity.