A typical mattress has a network of springs that provide support. If you sit on a mattress, the springs compress. A heavier person compresses the springs more than a lighter person. Use the properties of springs and spring forces to explain why this is so.
Assume the springs obey Hooke's law and the person is in equilibrium. If the person is heavier then the weight force is (blank) , so the upwad force of the springs must also be (blank) so the sum can be (blank).
To push up more, the springs must be (blank)