Mechanics questions | form five Physics

1. Briefly explain why the motion of a simple pendulum is not strictly simple harmonic?
2. Why the velocity and acceleration of a body executing simple harmonic motion (S.H.M.) are out of phase?

A body of mass 0.30​ kg executes simple harmonic motion with a period of 2.5sec and amplitude of 4.0×10^-2​ m . ​ Determine the:

1. Maximum velocity of the body.
2. Maximum acceleration of the body.
3. Energy associated with the motion.

A particle of mass 0.25​ kg vibrates with a period of 2.0 sec. If its greatest displacement is 0.4​ m what is its maximum kinetic energy?

1. Define moment of inertia of a body.
2. Briefly explain why there is no unique value for the moment of inertia of a given body?

1. State the principle of conservation of angular momentum.
2. A horizontal disc rotating freely about a vertical axis makes 45 revolutions per minute. A small piece of putty of mass 2.0×10^​-2​ kg falls vertically onto the disc and sticks to it at a distance of 5.0×10^-2​ m from the axis. If the number of revolutions per minute is thereby reduced to 36, calculate the moment of inertia of the disc.

1. Define the term tangential velocity.
2. Explain why the astronaut appears to be weightless when travelling in the space vehicle.

1. State Newton’s law of gravitation.
2. Use the law stated in (i) to derive Keppler’s third law.

1. Briefly explain why Newton’s equation of universal gravitation does not hold for bodies falling near the surface of the earth?
2. Show that the total energy of a satellite in a circular orbit equals half its potential energy.

1. What would be the length of a day if the rate of rotation of the Earth were such that the acceleration due to gravity ​ g ​ = 0 at the equator?
2. Calculate the height above the Earth’s surface for a satellite in a parking orbit.

Outline the motions that add up to make projectile motion.