Physics
Wheel is used with axle because :
- sliding friction is less than the rolling friction
- rolling friction is less than the sliding friction
- they work as the inclined plane
- they help us to change the direction of force.
Answer
rolling friction is less than the sliding friction
Reason — When a wheel rotates on its axle, the contact surfaces roll instead of slide. Rolling friction is much smaller than sliding friction, so using a wheel-and-axle arrangement greatly reduces the resistive force and makes it easier to move loads.
Related Questions
A pulley is used because it :
- has the mechanical advantage greater than one
- has 100% efficiency
- helps to apply the force in a convenient direction
- requires more effort to raise a less load.
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.