Physics
Match the following columns :
| Column A | Column B | ||
|---|---|---|---|
| (a) | Needle | (i) | class II lever |
| (b) | Door knob | (ii) | inclined plane |
| (c) | Ramp | (iii) | class I lever |
| (d) | Lemon crusher | (iv) | wheel and axle |
| (e) | See-saw | (v) | wedge |
Related Questions
Fill in the blanks :
(a) The useful work done by an actual machine is always …………… than the work done on the machine.
(b) In class II levers, the …………… is in between fulcrum and …………… .
(c) The mechanical advantage of class …………… lever is always less than 1.
(d) A pulley is used to change …………… .
(e) Mechanical advantage of an inclined plane is always …………… .
State whether the following statements are true or false:
(a) A boy does work while pushing a wall.
(b) A machine performs work by itself.
(c) In an ideal machine, work done on load is equal to the work done by effort.
(d) All levers are force multipliers.
(e) A pulley changes the direction of force.
(f) An inclined plane always has the mechanical advantage more than 1.
When is work said to be done by a force ?
What is energy?