Question

What is the efficiency of a machine with a work input of 3500 J and a work output of 3200 J? Think about what effort you are putting into the machine versus what you are getting out of it.


Select one:


a. 91%

b. 300%

c. 9%

d. 109%

Answer 1

Mechanical efficiency is given by:

\[E=\frac{work output}{work input}\]

You usually put electrical power in to a machine, and you usually get translational motion out of a motor.

Answer 2

= (output/ input) * 100

Answer 3

@welshfella oh! right right!

Answer 4

The effort you are putting in to a motor is in the form of:

P=VI;

P=Power
V=Voltage (V)
I=Current (A)

And the effort you are getting out of the motor is in the form of:

P=Tw

P=Power
T=Torque (Nm)
W=Angular velocity (rad/s)

Answer 5

okay so would the answer be 91%

Answer 6

Yes

Answer 7

okay thanks! ;)