Mechanics | Relativity Answers

Box going up elevator uniformly at 5m/'s falls off and hits bottom in 1.6secs

A) what time to reach max height?
B) height at which it fell?
C) height at 0.2 secs after falling

According to special theory of relativity, the speed ‘v’ of a free particle of mass ‘m’
and total energy ‘E’ is

a mass of 4 kg rests on a smooth plane inclined at 30 degrees to the horizontal. it is held in equilibrium by a light elastatic string attached to the mass on to a point on the plane. find the extension in the string if it is known that a force of would double the natural lenght of 1.25 meters

When you step on the brakes, what happens to the energy of the car? How does it happen?

A worker at the top of a 526-m-tall television transmitting tower accidentally drops a heavy tool. If air resistance is negligible, how fast (in m/s) is the tool going just before it hits the ground?

A cable stretches by an amount x under a certain load. if it is replaced by a cable of the same material but half as long and half the diameter, the same load will stretch it by ?

A 200 g mass is suspended at the 100 cm mark of metre-stick.The metre-stick has a massof 100 g. the magnitude of the sum of the moments about the 0 cm mark is ?

An astronaut leaves earth and travels at 0.92c. He spends 15 years exploring space. When he returns, how much time will have passed on earth ?

Sections 1 and 2 are at the beginning and end of the bend of the 200 mm diameter pipe in which the quantity of flow is 0.28 m3/s. The angle of deflection of the water is 40 degrees.Calculate the force that the liquid exerts on the bend if the pressure in the pipe is 50 kPa. Assume no loss of pressure round the bend.

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A 50 mm diameter stream of water strikes a 0.5 m by 0.5 m square plate which is at an angle of 30 degrees with the stream’s direction. The velocity of the water in the stream is 20 m/s and the jet strikes the door at its centre of gravity. If the plate is hinged at A, by neglecting the friction and self-weight of the plate, determine the normal force P applied at the upper edge of the plate to keep the plate in equilibrium. You may assume that the velocities of the jet remain unchanged after split.

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