Newton's second law says that acceleration of a particle is dependent on the forces acting upon the particle and the particle's mass. For a given particle, if the net force is increased, the acceleration is increased. For a given net force, the more mass a particle has, the less acceleration it has.
Ex. If you apply more force to an object, it accelerates at a higher rate, If you're pushing around a shopping cart, when you're moving at a regular pace, the cart goes at the same pace. If you accelerate your pace, the cart accelerates as well.
Hope this helps :)
-Julie