Jatinder Singh Solutions for Chapter: Machines, Exercise 2: TEST YOURSELF

Name a machine which is used to multiply force.

Name a machine which is used to: Multiply speed

Write the kind of lever as an example of the human body in the action of nodding of the head.
 

Write the kind of lever as an example of the human body :
In raising the load by the forearm. Also, show the position of load, effort and fulcrum in each case.

A man uses a crowbar of length $1.5 \mathrm{m}$ to raise a load of $75 \mathrm{kgf}$ by putting a sharp edge below the bar at a distance of $1 \mathrm{m}$ from his hand. Draw a diagram of the arrangement showing fulcrum (F), load (L) and effort (E) with their directions. State the kind of lever. Calculate:
$\left(\mathrm{i}\right)$ load arm,
$\left(\mathrm{ii}\right)$ effort arm,
$\left(\mathrm{iii}\right)$ mechanical advantage,
$\left(\mathrm{iv}\right)$ effort needed.

Give two reasons why efficiency of a single movable pulley system is not $100\%$.

Differentiate between a single fixed pulley and a single movable pulley.

How can you increase efficiency of a block and tackle pulley system ?