1-What is force?
Ans:- The push or pull of an object is
called force. It is a physical quantity that can change the speed,
state, direction and dimension of an object.
2-How many types of force?
Ans:- There are four types of force
1- Muscular force
2- Gravitational force
3- Magnetic force
4- Friction force
3-What is Muscular force?
Ans:- The force which is exerted by muscles
of the body is called muscular force.
Ex:- running, walking, lifting etc.
4-What is Gravitational force?
Ans:- Gravitational force is a force that
attracts a body towards the centre of the earth or towards any other physical
body having mass.
Ex:- leaves and fruits fall from a
tree downwards towards the ground due to the gravitational force.
5-What is magnetic force?
Ans:- The force exerted between two magnets
or a magnet and a magnetic material is called magnetic force.
6-What is friction force?
Ans:- Friction
force is the force that generated when two surfaces rub against one another.
It is the force which oppose the relative motion between the two surface
that are In contact with each other.
7-What is energy?
Ans:- The ability to do work is called energy.
8-Write two uses of light energy?
Ans:- Light energy helps us to see things.
Plants use light energy to make food
9-Write two uses of heat energy?
Ans:- Heat energy is used to cook food.
Heat energy is used to change water to
steam.
10-What is the use of electric energy?
Ans:- Electric energy is used to run washing machine, refrigerator, fan, iron. It is also used in running train and in industries.
11-What is machine?
Ans:- Anything that makes our work easier and faster by reducing the force is
called machine. It helps us to do a great deal of work with less effort.
12:- Write three advantage of machines?
Ans:- The three advantages of machines are
1- Machines help us to do work easily and with less effort.
2- machines help us to do work in less time.
3- Machines make our life easy and comfortable.
13-How many types of machine?
Ans:- There are two types of machine.
1- Simple machine
2- Complex machine
14-What is Simple machine?
Ans:- The devices which have moving or no moving parts that are used to modify motion and the magnitude of force in order to perform work is called simple machine.
15-How many types of simple machine?
Ans:- There are six types of simple machine.
1- lever
2- inclined plane
3- wedge
4- screw
5- wheel and axel
6- pulley
16-What is fulcrum?
Ans:- A fixed point around which a lever move is called
fulcrum.
17-What is load?
Ans:- The weight that is to be lifted by the lever is
called load.
18-What is effort?
Ans:- The
force that is applied on the lever is called the effort.
19-What is load arm?
Ans:- The
arm between the load and fulcrum is called load arm.
20-What is effort arm?
Ans:- The
arm between the effort and fulcrum is called effort arm.
21-What is lever?
Ans:- A simple machine that is made of a rod and a fulcrum
and it is free to move through a fixed point called fulcrum is called lever.
22-How many types of lever?
Ans:- There are three types of lever
1- class 1 lever or (first class
lever)
2- class 2 lever or (second class
lever)
3- class 3 lever or (third class lever)
23-What is class 1 lever?
Ans:- The lever in which the fulcrum is between the load
and the effort is called class 1 lever.
Ex- seissors, see-saw, pliers
24-What is class 2 lever?
Ans:- The lever in which the load is between the fulcrum
and the effort is called class 2 lever.
Ex- Bottle opener, Nut cracker etc.
25-What is class 3 lever?
Ans:- The lever in which the effort is between the fulcrum
and the load is called class 3 lever.
Ex- tweezer, fishing rod, broom, arm etc.
26-What is pulley?
Ans:- A pulley is a device consisting of a grooved wheel over which a rope or a chain is pulled in order to lift heavy objects. A single fixed pulley does not increase or decrease force. It simply changes the direction of the force.
27-How many types of pulley?
Ans:- There are four types of pulley.
1- fixed pulley
2- movable pulley
3- Compound system pulley
4- Complex system pulley
28-What is wheel and axle?
Ans:- The wheel and axle is a simple machine having a
wheel and an axel. The wheel is attached to the axle so that the force is
transferred from one to another
29-What is inclined plane?
Ans:- An inclined plane is a rigid sloping surface over
which heavy loads can be raised or lowered to a certain height or depth.
Steeper the inclined plane, greater will be the effort required to push up the
load.
Ex:- sloping ramps, flyovers, roads on
hills, etc.
30-Write two advantages of inclined plane.
Ans:- The two advantages of inclined plane are
1- Inclined plane is used to load
heavy things on trucks.
2- Inclined plane is used in
hospital as ramp to carry patients.
31-What is wedge?
Ans:- A wedge is double inclined plane. It is made up of
two inclined planes joined together in such a way that sharp edge is formed.
Ex:- a knife, an axe, etc.
32-What is screw?
Ans:- A
screw is a simple machine that appears like an inclined plane which have a
wounded thread around a rod with a pointed tip.
33-What is thread?
Ans:-The winding edge around the screw is called thread.
34-What is screw driver?
Ans:- A device that is used to screwed the screw into wood is called screw driver.
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