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?

Answer / Solution

UNSOLVED

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.

Answer / Solution

UNSOLVED

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.

Answer / Solution

UNSOLVED

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.

Answer / Solution

UNSOLVED

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.

Answer / Solution

UNSOLVED