Advertisements
Advertisements
प्रश्न
A crowbar of length 120 cm has its fulcrum situated at a distance of 20 cm from the load. Calculate the mechanical advantage of the crowbar.
उत्तर १
Total length of crowbar = 120 cm
Load arm = 20 cm
Effort arm = 120 − 20 = 100 cm
Mechanical advantage M.A. = `"Effort arm"/"Load arm"`
M.A. =` 100/20=5`
उत्तर २
By the principle of moments.
Moments of load about the fulcrum = Moment of efforts about the fulcrum
We have: W × 20 = P × (120 − 20)
`"W"/"P"=100/20`
= 5.
APPEARS IN
संबंधित प्रश्न
Define the term ‘work input’ and ‘work output’ in relation to a machine.
Answer the following in short.
Mention any two methods by which we can take care of machines.
State the kind of lever which always has mechanical advantage less than 1. Draw a labelled diagram of such a lever.
The mechanical advantage of an inclined place is always:
(a) less than 1
(b) equal to 1
(c) greater than 1
(d) nothing can be said
Give scientific reason for the following:
Passengers in a bus are pushed backward when it starts suddenly.
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?
Define mechanical advantage (M.A.) of the machine.
Comment on the statement ‘The mechanical advantage of a machine is greater than 1’. Give an example of a lever mechanical advantage is:
(i) greater than 1.
(ii) Equal to 1.
A simple machine enables us to lift a load of 10,000 N by the application of an effort of 500 N. However, when the point of application of the effort moves through 2.5 m, the load gets raised through 10 cm only. What are the values of the:
(i) M.A.
(ii) V.R. and
(iii) Efficiency of the machine?
