CLASS 9 / LAB ACTIVITY - 1

EXPERIMENT - 1

AIM
To establish relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance.

THEORY

According to Newton’s Second Law of Motion, the force acting on a body is directly proportional to the product of the mass of the body and the acceleration produced in the body by the application of the force. The acceleration takes place in the direction in which the force acts.

Newton’s Second Law of Motion precisely explains the relationship between force and acceleration.

Suppose a body of mass ‘m’ is moving by the application of a force ‘F’,  then the produced acceleration ‘a’ will be directly proportional to the applied force.

Acceleration ∝ Force 

F ∝ a 

 F ∝ m 

             Therefore, F = kma       ………… (1)

 Where k is constant of proportionality

 In SI unit, k =1

Therefore, F = ma

Importance of the Newton’s Second Law of Motion

•  Newton’s Second Law of Motion gives a quantitative measure of force.

                          F = ma

• The Second Law is a basic law of motion because both First and Third Law can be derived from this law.

MATERIAL REQUIRED

Wooden block and spring balance

PROCEDURE

1. A wooden block with a hook is placed on a table.
2. Note down the least count of the spring balance.
3. The spring balance is attached to the hook.
4. Hold the spring in such a way that the reading displayed in the spring balance can be noted down.
5. The applied force on the spring balance is gradually increased until it just starts to move.
6. The reading of the spring balance is noted.

OBSERVATION

Least count of the spring balance = value of 1 small division = …….g.wt

Trial No;	Mass of the block, M (kg)	Force required, F (N)

RESULT

Force applied to just move the block is directly proportional to the mass of the block.

ie, F ∝ M

PRECAUTIONS

1. A suitable spring balance to pull the block must be used.
2. The spring balance should be brought in elastic mode before doing the experiment.
3. The reading of the spring balance should be taken without any parallax error.
4. A smooth table or surface must be used.

      ANIMATIONS
https://www.youtube.com/watch?time_continue=71&v=1srdDxmWe34