1) Mechanical efficiency is the measure of the effectiveness of the performance of a mechanical system. T/F 2) When measuring mechanical efficiency, friction is not taken into account. T/F 3) If there was no friction on this Earth, cars would not be able to travel on roads. T/F 4) When calculating efficiency, the work output would always be greater than the work input. T/F 5) Efficiency of a machine can be improved by decreasing friction. T/F 6) Lubricants are solids and liquids that help decrease friction. T/F 7) Lubricants can be used to decrease thermal energy given off from light bulbs. T/F 8) Work output is the total amount of work you apply, including the work input and the friction caused by any moving parts in the machine. T/F
Mechanical Efficiency Problems
1) Tom uses 500 N of force to push a box up a 15 m ramp so that the box 2 m high from the ground. The force of gravity acting on the box is 100 N. What is the efficiency of the ramp? 2) An 800 N box is lifted using a second class lever with an input force of 400 N. The load arm is 2 m and the effort arm is 10 m. Calculate the mechanical efficiency of the lever? 3) A machine can do 400 J of work if 500 J of work is put into it. What is the efficiency of this machine?
Short Answer
1) Why is the mechanical efficiency never greater or equal to 100%? 2) Why is a Light Emitting Diode more efficient than an incandescent light bulb?
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Quiz
True and False
1) Mechanical efficiency is the measure of the effectiveness of the performance of a mechanical system. T/F
2) When measuring mechanical efficiency, friction is not taken into account. T/F
3) If there was no friction on this Earth, cars would not be able to travel on roads. T/F
4) When calculating efficiency, the work output would always be greater than the work input. T/F
5) Efficiency of a machine can be improved by decreasing friction. T/F
6) Lubricants are solids and liquids that help decrease friction. T/F
7) Lubricants can be used to decrease thermal energy given off from light bulbs. T/F
8) Work output is the total amount of work you apply, including the work input and the friction caused by any moving parts in the machine. T/F
Mechanical Efficiency Problems
1) Tom uses 500 N of force to push a box up a 15 m ramp so that the box 2 m high from the ground. The force of gravity acting on the box is 100 N. What is the efficiency of the ramp?
2) An 800 N box is lifted using a second class lever with an input force of 400 N. The load arm is 2 m and the effort arm is 10 m. Calculate the mechanical efficiency of the lever?
3) A machine can do 400 J of work if 500 J of work is put into it. What is the efficiency of this machine?
Short Answer
1) Why is the mechanical efficiency never greater or equal to 100%?
2) Why is a Light Emitting Diode more efficient than an incandescent light bulb?