QUESTION 5
5.1 Define work
5.2 A person pushes with 100 N against a solid wall for 1 minute without the wall moving. Determine the work done on the wall.
5.3 A 60 kg mass is lifted vertically 52 m without 45 seconds
Determine the following:
5.3.1 The work done in lifting the mass
5.3.2 The average power required to lift the mass
5.3.3 The efficiency of the lifting device if the input power is 1000 watt.
5.4 A constant force of 80 N is applied on the circumference of a gear wheel that has a diameter of 300 mm . Calculate the work done on the gear wheel per single revolution.
5.5 A train with a mass of 200000 kg has a tractive resistance of \( 12 \mathrm{~N} / \mathrm{kN} \) (wind, friction, etc.) If the train is moving on a level at \( 20 \mathrm{~m} / \mathrm{s} \), determine the following:
5.5.1 The total tractive resistance of the train
5.5.2 The power required by the locomotive to maintain this speed
5.5.3 The efficiency of the locomotive, if the input power is 1 MW (1Megawatt) and the speed is constant
5.6 A water pump delivers \( 0.3 \mathrm{~m}^{3} \) of water per minute to a height of 10 m Determine the following:
5.6.1 The weight of water delivered per second
5.6.2 The input power to the pump if its efficiency is \( 80 \% \)
5.7 A load with a weight of 2500 N is lifted through a height of 40 m by means of a cable with a weight of \( 25 \mathrm{~N} / \mathrm{m} \), which is wound onto a drum at the top. Sketch a reference graph.
5.8 Determine the following from the graph sketched in QUESTION 5.7
