Engineering Answers

1. if the voltage across an element is 8V and the current i entering the positive terminal is as shown, find the power delivered to the element at t=7 ms and the total charge and total energy delivered to the element between 1 and 10 ms.
2. a copper wire has a resistance of 2 ohms it was drawn under pressure so that its diameter is reduced to one half its original diameter. the new resistance of wire is...

Background A villager in South Africa has an inhabitant of five hundred people. It is 200 km from the nearest Eskom substation based on line of sight. Presently, the only source of electric power in the village is diesel generator. Due to Covid-19, the company that used to maintain the generator has folded up, consequently, the villagers have no electricity. Aim Design a standalone (off grid) Photovoltaic (PV) system with special reference to the village in South Africa with the following PV panel generation factors: Group Number PV panel generation factor A 8.5 B 8 C 7.8 D 7 E 7.5 G 7.2 F 8.4 G 7.5 Use any medium of communication available to group yourselves into a maximum of eight (8) members per group and name your groups as per the group numbers in the table above respectively. A typical platform to be used for communication could be myUnisa (discussion forum), Whatsup, Zoom, MS Teams etc. Choose PV panel generation factor based on the group number.

A jet of water with 50 mm diameter impinges on a curved vane

and is deflected through 135º. The vane moves in the same

direction as that of jet with a velocity of 5 m/sec. If the rate of

flow of water is 30 lt/sec, determine (a) force on the vane in the

direction of motion, (b) work done per sec and (c) efficiency.

A 20 cm diameter jet of water strikes a curved vane with a velocity of 30 m/s. The inlet vane angle is zero and the outlet angle is 25°. Find the resultant force on the vane

(a) when the vane is fixed;

(b) when the vane is moving with a velocity of 15 m/s in the direction of jet.