Advertisements
Advertisements
Question
Can a machine have an efficiency of 100%? Give a reason to support your answer.
Advertisements
Solution
Efficiency of a machine is always less than 100% as output energy is always less than the input energy because some energy is lost to overcome friction.
APPEARS IN
RELATED QUESTIONS
What is the principle on which a machine works?
Name six simple machines. Give an example of each machine.
Why is a machine not 100% efficient?
State the kind of lever which always has mechanical advantage less than 1. Draw a labelled diagram of such a lever.
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?
Give an example where a machine is used to obtain gain in speed.
Which machine will you use to do the following work? Write their type.
To lift bricks to the top of a tall building.
What is meant by simple machines?
Name the levers mentioned in the following passage. Identify the fulcrum, load, and effort of each and say which type of lever it is.
Ravi and Savita sit on a seesaw in a garden. In the meantime, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.
Simple machines usually exchange a larger force to move a heavy object.
