ICSE Class 8 Physics Case Study Based Questions
Understand the moment of force through a practical steering wheel example and check your learning using interactive questions and answers.
Moment of Force Case Study
This Class 8 Physics activity explains how the magnitude of force, the perpendicular distance from the axis of rotation and the direction of force affect the turning effect produced on an object.
Steering Wheel and Moment of Force
During a school trip, Samay carefully watched the bus driver. The bus had a large steering wheel. The driver held the steering wheel near its outer edge while turning. Samay tried holding the wheel close to the centre and found it difficult to turn. He also noticed that turning became harder whenever the force was applied at an angle.
Case Study Questions and Answers
Select each question to reveal its answer.
1. Why was Samay unable to turn the steering wheel easily when he held it close to the centre?
When Samay held the steering wheel near the centre, the perpendicular distance from the axis of rotation became very small. Since the moment of force depends on the distance from the pivot, a smaller distance produced a smaller turning effect. Therefore, turning the wheel became difficult.
2. Why does holding the steering wheel at the outer edge make turning easier?
At the outer edge, the distance from the centre of rotation is maximum. A greater perpendicular distance produces a greater moment of force. Therefore, less effort is needed to turn the steering wheel.
3. Why does turning become harder when the force is applied at an angle?
The greatest turning effect is produced when the force acts perpendicular to the steering wheel. When the force is applied at an angle, only a part of the applied force contributes to rotation. Therefore, the moment of force decreases and turning becomes harder.
4. Why do buses usually have larger steering wheels than cars?
Buses are large and heavy vehicles that require a greater turning effect. A larger steering wheel has a greater radius, which increases the perpendicular distance from the axis of rotation. This helps the driver produce a greater moment of force with less effort.
5. Which formula explains the working of a steering wheel?
The turning effect produced on the steering wheel is explained by the formula for the moment of force.
Moment of Force = Force × Perpendicular DistanceM = F × d
6. Name the two factors on which the moment of force depends.
The moment of force depends on the magnitude of the applied force and the perpendicular distance of the force from the axis of rotation.
