== F=m*a Force = mass * speed a = F/m For the same Force F
the speed is big for small mass
the speed is small for big mass == The more mass something has, the more force is required to accelerate it to a given speed. The less mass something has, the less the force required to accelerate it to a given speed. Simple and easy. For a given amount of force, the less the mass it is applied to, the higher the speed that will result. The more the mass to which it is applied, the lower the speed that will result. It's just that simple.