10 questions · Form 2 Science Bab 8: Force and Motion
A balanced seesaw has a 300 N child sitting 2.0 m to the left of the pivot. How far from the pivot must a 400 N child sit on the right side to maintain balance?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. A balanced seesaw has a 300 N child sitting 2.0 m to the left of the pivot. How far from the pivot must a 400 N child sit on the right side to maintain balance?
Answer: A
Principle of Moments: Anticlockwise Moment = Clockwise Moment. 300 N × 2.0 m = 400 N × distance. Distance = 600400 = 1.5 m.
2. Which instrument is used in the laboratory to measure the magnitude of a force?
Answer: B
A spring balance (dynamometer) measures force based on the extension of an elastic spring proportional to the force applied.
3. Why does a suction cup stick firmly to a smooth glass window when pressed flat against it?
Answer: B
Pressing the cup removes air inside, creating a partial vacuum; higher atmospheric pressure outside presses the cup tightly against the glass.
4. Which tool acts as a Third Class Lever?
Answer: C
A fishing rod is a third class lever (F - E - L), where effort is applied by the hand between the handle pivot and the load at the line tip.
5. Why are wide, continuous tracks used on heavy army tanks instead of standard narrow rubber tires?
Answer: B
Wide tracks increase ground contact surface area, lowering pressure (P = FA) so heavy vehicles do not sink into soft terrain.
6. Which set of items belongs to First Class Levers (Pivot located between Load and Effort)?
Answer: B
In scissors and crowbars, the fulcrum (pivot) lies between the effort point and the load point (L - F - E).
7. Which type of force always acts directly opposite to the direction of motion between two moving touching surfaces?
Answer: B
Frictional force resists relative motion and acts in the direction opposite to movement.
8. An object floats in water when the upward buoyant force is equal to what quantity?
Answer: B
An object floats in equilibrium when the upward buoyant force equals the downward weight (gravitational force) of the object.
9. In a second class lever, what is the position of the Load relative to the Pivot and Effort?
Answer: A
In second class levers (F - L - E), the Load is located between the Pivot and the Effort (e.g., wheelbarrow).
10. A force of 200 N acts perpendicularly on a surface area of 2 m². What is the resulting pressure exerted on the surface?
Answer: B
Pressure P = Force / Area = 200 N2 m² = 100 Pa (or Nm²).