Mechanics | Relativity Answers

The position of a particle is given by S = (2t^2 − 8t + 6)m, where t is in seconds. Determine the time when the velocity of the particle is zero, and the total distance travelled by the particle when t = 3 s.

The work done on a reversed heat engine is 100kg whilst the heat transfer to the engine
from the low temperature is 300kJ. Determine the heat transfer to the high temperature reservoir and the COP as a refrigerator and as a heat pump.

A steady flow of steam enters a condenser with a specific enthalpy of 2300 kJ/kg and a velocity of 350m/s. The condensate leaves the condenser with a specific enthalpy of 160 kJ/kg and a velocity of 70 m/s. calculate the heat transfer to the cooling fluid per kilogram of steam condensed.

An air compressor which compresses air at constant internal energy rejects 80 kJ of heat to the cycling water for every kilogram of air. Calculate the work done during compression stroke per kilogram of air.

A fluid is heated reversibly at a constant pressure of 1.05 bar until it has a specific volume of 0.1m3/kg. It is then compressed reversibly according to a law pv= Constant to pressure of 4.2bar, then allowed to expand reversibly according to a law pv1.7= Constant, and is finally heated at constant volume back to the initial conditions. The work done in the constant pressure process is 1515Nm, and the mass of fluid present is 0.2 kg. Calculate the network of the cycle and sketch the cycle on a p-v diagram.

0.05 m3 of a gas at 6.9 bar expands reversibly in a cylinder behind a piston according to the law pv1.2= Constant, until the volume is 0.08 m3. Calculate the work done by the gas and sketch the process on a p-v diagram.

1 kg of a fluid is compressed reversibly according to a law pv = 0.25, where p is in bar and v is in m3/kg. The final volume is one-fourth of the initial volume. Calculate the work done on the fluid and sketch the process on a p-v diagram.

A fluid at 10 bar is enclosed in a cylinder behind a piston, the initial volume being 0.05 m .Calculate the work done by the fluid when it expands reversibly according to a law pv3= C to a final volume of 0.06 m3.

a train travels 50 km in half hour. it the stops at a station for 20 mins, before traveling for 2 hours at an average speed of 90 km/h what was the trains average speed over the whole journey

A student competing in a rock slinging contest propels a rock with an initial speed of 22 m/s at an angle of 40.0° above the horizontal from the top of a high cliff. If the rock lands 78 m from the bottom of the cliff, how high is the cliff? Assume no air resistance.