Question

What is the relation between the different types of energies during pendulum motion where friction can be ignored?

a) The total energy is split into kinetic and potential energies. The values of the different types of energy constantly changing.

b) The pendulum has constant values of kinetic and potential energies.

c)The potential energy continues to increase at the expense of the kinetic energy.

d)The kinetic energy continues to increase at the expense of the potential energy.

e) Both kinetic and potential energy continuously decrease. They do so in identical ways.

f) Kinetic and potential energy change continuously, but they do so in unrelated ways.

Answer 1

Here we apply concept of simple harmonic motion and mechanical energy conservation.

Here, we can see, three positions are shown À B' & Ć B' is lowest position i f ' are extreme position If we neglect friction, then sun of Kinetic energy & potential energy at all locations will be constant K + VA = KB + UB = ų tuc We can see, Up <UA Up < uc ko g> 4 4 К > К. so total energy is split into kinetic & potential energy. Also we can see value of different energy ie. Kinetic as well as potential energy is changing continuously so option (a) es correct. (6) Wrong, as Potential energy & kinetic Energy is changing' not constant (c) Wrong, as Potential energy increases from B tol f when it returns then potential energy decreases o w •

- (d) Wrong As Kinetic Energy decreases too when . it goes from B to C - (el Wrong, as when kinetic Energy decreases then - potential energy increases & vice versa. • (6) Wrong, as sum of Kinetic & Potential energy us constant so Kinetic energy decreases as much potential energy increases.