1. Suppose two buckets are hanging above the ground. One bucket is filled with sand and other is empty. Initially both buckets are at the state of rest. Now if we want to push these buckets into a swinging motion, the bucket with sand would require more force, because it has more mass or inertia. 2. It is always difficult to pull out a truck from the mud than a car, only because a truck has more mass than a car.