We get heat on earth from the sun. Energy from the sun is transferred through space and through earths atmosphere to the earths surface. And since this warms the earth surface it creates heat.
Gear because each spike is a wedge shape that adds a mechanical advatage
Initially, the spring stretches by 3 cm under a force of 15 N. From these data, we can find the value of the spring constant, given by Hook's law:

where F is the force applied, and

is the stretch of the spring with respect to its equilibrium position. Using the data, we find

Now a force of 30 N is applied to the same spring, with constant k=5.0 N/cm. Using again Hook's law, we can find the new stretch of the spring: