Physics
State whether the following statements are true or false. Correct the false statements.
(a) A girl riding a bicycle is getting zero work done.
(b) When the value of mechanical advantage is equal to one, it means that effort is equal to load.
(c) In class III lever, the fulcrum is between the load and the effort.
(d) In a fixed pulley, the pulley can move.
(e) Tyres of cars and buses are examples of wheel and axle.
Answer
(a) False
Corrected Statement — Work done on an object is the product of force and distance and since the girl is covering a significant distance by applying muscular force on the bicycle so work done is not zero.
(b) True
(c) False
Corrected Statement — In class III lever, the effort is between the fulcrum and the load while in class I lever, the fulcrum is between the effort and the load.
(d) False
Corrected Statement — In a fixed pulley, the pulley is attached to a hook or a wall and doesn't move while a movable pulley moves with the load.
(e) True
Related Questions
Some of the facts that you have learnt till now are listed below. Tick (✓) the facts that are correct and cross (x) the facts that are incorrect.
(a) Efficiency of a machine can be 100%.
(b) A wheel and axle move together.
(c) A wedge is a combination of an axle and inclined plane.
(d) Screw acts as a fastener.
(e) Screwdriver is an example of screw.
Fill in the blanks.
(a) The ratio of the load lifted by a machine to the effort applied on it is called …………… .
(b) Work done on an object is the product of …………… and …………… .
(c) There are three types of levers based on the positions of ……………, …………… and …………… .
(d) The ratio of work done by a machine to the work done on the machine is termed as …………… of the machine.
(e) The arrangement of several pulleys to pick heavy loads is called …………… .
Which of the following is not a simple machine?
- Bicycle
- Scissors
- Doorknobs
- Bottle openers