Mechanics questions | form five Physics

A satellite of mass 600kg is in a circular orbit at a height 2×10​⁶ ​km above the earth’s surface.
Determine the:

1. Orbital speed.
2. Gravitational potential energy.

1. What would happen if gravity suddenly disappears?
2. Two base of a mountain are at sea level where the gravitational field strength is 9.81​ N / ​kg . ​If the value of gravitational field at the top of the mountain is 9.7​ N / ​ kg , ​ calculate the height of the mountain above the sea level.

1. Why is flywheel designed such that most of its mass is concentrated at the rim? Briefly explain.
2. Estimate the couple that will bring the wheel to rest in 10 seconds when a grinding wheel of radius 40 cm and mass 3 kg is rotating at 3600 revolutions per minute

1. Why an ice skater rotates at relatively low speed when stretches her arms and leg outward?
2. Calculate the moment of inertia of a sphere about an axis which is a tangent to its surface given that the mass and radius of the sphere are 10kg and 0.2m respectively.

1. Provide two typical examples of simple harmonic motion (S.H.M.).
2. Why the velocity and acceleration of a body executing simple harmonic motion are out of phase?

1. The period of a particle executing simple harmonic motion (S.H.M.) is 3 seconds. If its amplitude is 25 cm, calculate the time taken by the particle to move a distance of 12.5cm on either side from the mean position.
2. A person weighing 50 kg stands on a platform which oscillates with a frequency of 2Hz and of amplitude 0.05m. Find his/her minimum weight as recorded by a machine of the platform.

1. In which aspect does circular motion differ from linear motion?
2. Why there must be a force acting on a particle moving with uniform speed in a circular path?

1. Figure 1 shows a particle moving in a semi-circular path AB of radius 6m with constant speed of 12ms^-1​ . Calculate its average velocity.

2. A stone tied to the end of string 80cm long, is whirled in a horizontal circle with a constant speed making 25 revolutions in 14 seconds. Determine the magnitude of its acceleration.

1. Why the weight of a body becomes zero at the centre of the earth?
2. How far above the earth surface does the value of acceleration due to gravity becomes 36% of its value on the surface?

1. Compute the period of revolution of a satellite revolving in a circular orbit at a height of 3400 km above the earth’s surface.
2. Prove that the angular momentum for a satellite of mass ​ M_s revolving  round the earth of mass ​ M_e ​ in an orbit of radius ​ r ​ is equal to