Advertisements
Advertisements
Question
Define the term ‘work input’ and ‘work output’ in relation to a machine.
Advertisements
Solution
Work input is work done on a machine equal to the effort force times the distance through which the force is applied.
Work output is work that is done by a machine and equals resistance force times the distance through which the force is applied.
For an ideal machine, the work output is equal to the work input, i.e., the efficiency.
APPEARS IN
RELATED QUESTIONS
Name six simple machines. Give an example of each machine.
Answer the following in short.
Mention any two methods by which we can take care of machines.
Give a reason for the following.
Machines are able to make our work convenient.
Fig show a system of four pulleys. The upper two pulleys are fixed and the lower two are movable.

(i) Draw a string around the pulleys. Also show the place and direction in which the effort is applied.
(ii) What is the velocity ratio of the system?
(iii) What is the mechanical advantage of the system?
(iv) What assumption do you make in arriving at your answer in part (iii)?
Define Mechanical advantage
Fig. shows a spade. It is being used to lift soil weighing 30N from the ground.

(a) Mark the direction of the least force on the handle necessary to keep the spade balanced.
(b) Calculate the least force on the handle necessary to keep the spade balanced (the weight of the spade is negligible).
(c) If the left hand was move towards the soil on the spade, would the force on the handle necessary to keep the soil balance the greater or less? Give a reason for your answer.
(d) To which class of lever does the spade belong?
Write an expression for the mechanical advantage of an inclined plane.
The ______ in the centre, the ______ on one side and the ______ on the other side make a lever of the second order.
Which machine will you use to do the following work? Write their type.
To draw water from a well.
Rearrange the letters and find out the name of the tool.

R L E V E
| ______ | ______ | ______ | ______ |
