Activity 8.2:
Aim: To measure force.
Materials: Weight (50 g), string, sandpaper and wooden block
Apparatus: Retort stand with clamp and spring balance
Instruction
(A) Weight of object
1. Hang a 50 g weight at the end of a spring balance (Photograph 8.3).
2. Record the reading of the spring balance.
3. Add up to five weights and record the reading of the spring balance.
Questions
1. What is the physical quantity measured by the spring balance?
2. What is the unit of the physical quantity for your answer in question 1?
3. What happens to the reading of the spring balance when the number of weights is increased? Explain your answer.
(B) Frictional force
1. Set up the apparatus as shown in Photograph 8.4.
2. Pull the spring balance until the wooden block starts to move and record the reading of the spring balance.
3. Repeat this activity by pulling the wooden block on a sandpaper.
Questions
1. The wooden block moves only when enough pulling force acts on it. What type of force is resisting the movement of the wooden block?
2. State the difference in the reading of the spring balance when the wooden block is pulled on the table and when it is pulled on the sandpaper. What is the force involved that causes the difference between the readings of the two spring balances?
Answer:
A
1. Force
2. newton (N)
3. Reading of the spring balance increases because the number of weight increases.
B
1. Frictional force
2. Reading of spring balance when wooden block is pulled on the surface of the table is lower compared to when the wooden block is pulled on the surface of sandpaper. Frictional force causes the difference in the readings.
Aim: To measure force.
Materials: Weight (50 g), string, sandpaper and wooden block
Apparatus: Retort stand with clamp and spring balance
Instruction
(A) Weight of object
1. Hang a 50 g weight at the end of a spring balance (Photograph 8.3).
2. Record the reading of the spring balance.
3. Add up to five weights and record the reading of the spring balance.
Questions
1. What is the physical quantity measured by the spring balance?
2. What is the unit of the physical quantity for your answer in question 1?
3. What happens to the reading of the spring balance when the number of weights is increased? Explain your answer.
(B) Frictional force
1. Set up the apparatus as shown in Photograph 8.4.
2. Pull the spring balance until the wooden block starts to move and record the reading of the spring balance.
3. Repeat this activity by pulling the wooden block on a sandpaper.
Questions
1. The wooden block moves only when enough pulling force acts on it. What type of force is resisting the movement of the wooden block?
2. State the difference in the reading of the spring balance when the wooden block is pulled on the table and when it is pulled on the sandpaper. What is the force involved that causes the difference between the readings of the two spring balances?
Answer:
A
1. Force
2. newton (N)
3. Reading of the spring balance increases because the number of weight increases.
B
1. Frictional force
2. Reading of spring balance when wooden block is pulled on the surface of the table is lower compared to when the wooden block is pulled on the surface of sandpaper. Frictional force causes the difference in the readings.