Activity 7.2 Let us experiment to demonstrate conservation of mechanical energy. Class 9

Activity 7.2 Let us experiment to demonstrate conservation of mechanical energy. Class 9

Activity 7.2 Let us experiment

Aim: To demonstrate conservation of mechanical energy using a simple pendulum. Take a simple pendulum and take the bob to one side to point P and let it go. Observe it at the extreme points of the oscillations.

Observation: At point P, the pendulum bob has potential energy U = mgh where h is height from lower most point.

At point Q, potential energy = 0 and kinetic energy gained at lower most point = 1/2 mv²

At point R on other side of the pendulum where bob stops, kinetic energy = 0 and potential energy U = mgh where his height from lowermost point. The pendulum bob reaches the same height it

Conclusion: Mechanical energy of the bob remains constant throughout the oscillation demonstrating conservation of mechanical energy. In real life, the pendulum gradually slows due to friction at the support and air resistance, which convert mechanical energy to heat.