Mechanics questions | form five Physics

A hose with a nozzle 80mm diameter ejects a horizontal stream of water at a rate of . With what velocity will the water leave the nozzle?. What will be the force exerted on a vertical wall situated close to the nozzle and at right-angles to the stream of water, if, after hitting the wall.

1. The water falls vertically to the ground
2. The water rebounds horizontally?

(Density of water =1000kg m^-3)

Answer / Solution

UNSOLVED

What is the connection between force and momentum? A helicopter of total mass 1000kg ia able to remain in a stationary position by imparting a uniform downward velocity to a cylinder of air below it of effective diameter 6m. Assuming the density of air to be , calculate the downward velocity given to the air.

Answer / Solution

UNSOLVED

An astronaut is outside her space capsule in a region where the effect of gravity can be neglected. She uses a gas gun to move herself relative to the capsule. The gas gun fires gas from a muzzle of area 160mm² at a speed of 150ms^-1 . The density of the gas is 0.800 kg m^-3 and the mass of the astronaut , including her space suit , is 130 kg. Calculate:

1. The mass of gas leaving the gun per second
2. The acceleration of the astronaut due to the gun, assuming that the change in mass is negligible

Answer / Solution

UNSOLVED

Sand is poured at a steady rate of on to the pan of a direct reading balance calibrated in grams. If the sand falls from a height of 0.20 m on to the pan and it does not bounce off the pan then, neglecting any motion of the pan, calculate the reading on the balance 10 seconds after the sand first hits the pan.

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UNSOLVED

A pebble is dropped  from rest at the top of a cliff 125m high. How long does it take to reach the foot of the cliff, and with what speed does it strike the ground? With what speed must a second pebble be thrown vertically down-wards from the cliff top if it is to reach the bottom in 4 seconds?(Ignoring resistance of air)

Answer / Solution

UNSOLVED