Advertisements
Advertisements
प्रश्न
What is an ideal machine?
Advertisements
उत्तर
A machine in which no part of the work done on the machine is wasted is called an ideal or perfect machine. Thus, for an ideal machine, the work output is equal to the work input, i.e., the efficiency of an ideal machine is 1 (or 100 percent).
APPEARS IN
संबंधित प्रश्न
State whether the following statement is True or False.
A machine performs work by itself.
What do you understand by a machine?
State if the following statement is true or false. Correct the statement if it is false.
There are four types of simple machines.
State if the following statement is true or false. Correct the statement if it is false.
Work done by a machine is always more than the work done on a machine.
Why is a machine not 100% efficient?
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.
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 Velocity Ratio
Give an example of the following use of a machine to change the direction of force.
A cook used a ‘fire tong pair’ of length 32 cm. to lift a piece of burning coal of mass 500 g. If he applies his effort at a distance of 8 cm from the fulcrum, what is his effort? Assume friction etc. to be absent. Also, obtain values of the M.A. and the V.R. of this ‘machine’.
