Mechanics questions | form five Physics

1. Determine the least number of pieces required to stop the bullet if a rifle bullet loses 1/20 of its velocity when passing through them.
2. A man of 100 kg jumps into a swimming pool from a height of 5 m. If it  takes 0.4 seconds for the water in a pool to reduce its velocity to zero, what average force did the water exert on the man?

1. Justify the statement that projectile motion is two dimensional motion.
2. A rocket was launched with a velocity of 50 m/s from the surface of the moon at an angle of 40° to the horizontal. Calculate the horizontal distance covered after half time of flight.

1. Show that the angle of projection ​ θ° ​ for a projectile launched from the origin is given by θ° ​ = tan​^-1​ (4​ h_m ​/​ R) ​ , where R stands for horizontal range and ​ h​_m is the maximum vertical height.
2. A person weighing 50kg stands on a platform which oscillates with a frequency of 2Hz and of amplitude 0.05 m. Find his/her minimum weight as recorded by a machine of the platform.

1. Under what condition a passenger in a lift feels weightless?
2. Calculate the tension in the supporting cable of an elevator of mass 500kg which was originally moving downwards at 4m/s and brought to rest with constant acceleration at a distance of 20m.

1. The rotating blades of a hovering helicopter swept out an area of radius 2m imparting a downward velocity of 8m/s of the air displaced. Find the mass of a helicopter.
2. Compute the mass of water striking the wall per second when a jet of water with a velocity of 5m/s and cross-sectional area of 3 × 10​^-2 ​ m² striked the wall at the right angle losing its velocity to zero.

1. How does projectile motion differ from uniform circular motion?
2. A rifle shoots a bullet with a muzzle velocity of 1000m/s at a small target 200m away. How high above the target must the rifle be aimed so that the bullet will hit the target?

1. Where does the object strike the ground when thrown horizontally with a velocity of 15m/s from the top of a 40m high building?
2. Find the speed of travel when a man jumps a maximum horizontal distance of 1m spending a minimum time on the ground.

What is meant by the following terms as used in simple harmonic motion (S.H.M.)?

1. Periodic motion.
2. Sketch a labeled graph that represents the total energy of a particle executing simple harmonic motion (S.H.M.).

1. List four important properties of a particle executing simple harmonic motion (S.H.M.).
2. Sketch a labeled graph that represents the total energy of a particle executing simple harmonic motion (S.H.M.).

The periodic time of a body executing S.H.M. is 4 seconds. How much time interval from time, t = 0 will its displacement be half its amplitude?