Question

(a) Define the term 'force'.
(b) State the various effects of force.
Give any one answer ​

Answer 1

Force: A pull or push on a object or body is called force.

⇒ Vector quantity

⇒ S.I Unit = kg.m/s or Newton ( N )

⇒ C.G.S = 1 dyne [ 1 N = 10⁵ dyne ]

Force are used in our everyday actions such as Pulling, Pushing kicking, squeezing, lifting, etc..

The various effects of force :

• A force can change the speed of a moving objects.

• A force can cause motion.

• A force can stop motion.

• A force can change the direction of a moving object.

• A force can change the shape and size of an object.

Newton's law of motion:

Newton's First law of motion/Galileo's law if inertia:

If object is at rest ,it has tendency to remain at rest .Only if an net force applies on it ,it moves. If object in motion, it has tendency to keep moving with constant speed in a straight line . Only if a net force applies on it ,Speed or direction of motion change.

Newton's Second law of motion:

Force applied on a body is equal to its rate of change of momentum.

u v

○ ----------------> ○

m m

u = initial velocity

v = final velocity

m = Mass of a body

F ∝ change in momentum / time taken

F ∝ mv - mu / t

F ∝ m ( v - u ) / t

F ∝ m × a [ v - u / t = a ]

F = k × m × a [ k is constant ]

F = m × a

Newton's third law of motion:

When one object applies force on objects to another object also applies force are of some magnitude but in opposite directions.

☆ Every action has an equal and opposite reaction.

Some terms:

• Inertia: The tendency of a body to remain at rest or if motion, continuous moving in a straight line .

• Momentum: The product of its mass and velocity of a body is called momentum.

Answer 2

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☆ SHORT DEFINITION FORCE:

(a) The term force refers the strength and energy applied to a object or things.

☆ EXAMPLE:

➠ If I am giving a push or pull to an object than this is known as FORCE. Anything which is applied with enough energy and strength is force.

☆ FORMULA OF FORCE:

➠ $\sf Force = Mass \times Acceleration.$

(b) Force have power to give several effects such as follows:

➠ Using force or pull we can pull a object.

➠ The effect of force can stop a moving object.

➠ Force helps us in changing the movement of an object.

☆ REASON:

➠ The reason why force can do several effects because force is formed by the pressure of energy and the strength given to a object and hence the force helps to push/pull or stop or change the direction of the object.