# Conservation of Energy

### Problems

Problem :

A skier glides down a frictionless hill of 100 meters, the ascends another hill, of height 90 meters, as shown in the figure below. What is the speed of the skier when it reaches the top of the second hill?

The skier moves from point A to point B

Problem :

What was the change in potential energy in the last problem, given that the mass of the skier is 50 kg?

Problem : What is the total energy of the mass-spring system shown below? The mass is shown at its maximum displacement on the spring, 5 meters from the equilibrium point.

Mass-spring system

Problem :

A particle, under the influence of a conservative force, completes a circular path. What can be said about the change in potential energy of the particle after this journey?

Problem :

A pendulum with string of length 1 m is raised to an angle of 30 o below the horizontal, as shown below, and then released. What is the velocity of the pendulum when it reaches the bottom of its swing?

A pendulum, shown in its initial and final positions.

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