EVS CH-11 SIMPLE MACHINES( NOTEBOOK AND WORKBOOK EXERCISE)
CH- 11 SIMPLE MACHINES( NOTEBOOK EXERCISE)
NEW WORDS
1.inclined
2.rigid
3.fulcrum
4.axle
5.groove
6.wedge
7.cylindrical
8.lever
9.screw
10.pulley
NEW TERMS
1.inclined – sloping
2.rigid – non-flexible
Name the type of simple machine that can be used for doing the following activities.
a. To load a truck with boxes of goods. INCLINED PLANE
b. Cut a fruit. WEDGE
c. Opening a door using a doorknob. WHEEL AND AXLE
d. Opening a bottle using a bottle opener. CLASS 2 LEVER
e. To catch a fish using a fishing rod. CLASS 3 LEVER
Answer the following questions.
a. What are simple machines?
ANS. A machine is a tool that helps us move a load by applying less force. The force applied is called effort.
b. What is a screw?
ANS. A screw is a simple machine which is a modified inclined plane that winds around a cylindrical core to form a spiral.
Nuts and bolts, and grooves on a jar are examples of the simple machine screw.
c. Why a wheel cannot be used as a machine without an axle?
ANS. A piece of rod passing through the centre of a wheel is called an axle. The axle supports the wheel and allows the wheel to turn on the same axis. Without an axle, a wheel cannot be used as a machine.
d. Give an example in the human body where a class- one lever is found.
- ANS. An example of a class one lever is the joint between the skull and the vertebral column.
- The vertebral column is the fulcrum.
- When you nod, the neck muscles at the back of the skull provide the force (effort) to lift your head up against the weight of the head (load).
- When the neck muscles relax, your head nods forward.
