Introduction
This PSLE Science question tests understanding of multiple forces acting at the same time — friction, gravitational force, and magnetic force.
Students must determine which forces act on a magnet placed on a slope and why the magnet moves the way it does.
The teacher clearly explains how each force affects the magnet’s motion using a force table and diagram.
The Question
A magnet is placed on a slope. Depending on whether magnetic repulsion or attraction is involved, the magnet may move up or down the slope.
Students must identify which forces act on the magnet in the given scenario.
Options include combinations of:
- Friction
- Gravitational force
- Magnetic force
Step-by-Step Explanation (Following Teacher’s Working)
1. Gravitational Force
Gravity always acts downwards, pulling the magnet down the slope.
✔ This force is definitely acting.
2. Friction
Friction opposes motion, so if the magnet moves down, friction acts up the slope.
✔ Friction is also acting.
3. Magnetic Force
In the teacher’s explanation, another magnet is placed at the top of the slope.
Because similar poles face each other, the magnets repel.
Repulsion pushes the magnet down the slope, adding to gravity.
✔ Magnetic force is acting.
4. Fill in the Forces Table Exactly as Teacher Did
| Force | Acting? |
| Friction | ✔ |
| Gravitational force | ✔ |
| Magnetic force | ✔ |
All three forces must be ticked.
✅ Correct Answer: Option (4)
This is the only option where all three forces are marked as acting.
Key Concepts
| Concept | Why It Matters |
| Friction | Opposes motion; acts up the slope when object slides down |
| Gravity | Pulls objects downward; causes sliding |
| Magnetic Force | Can attract or repel depending on pole orientation |
| Multiple Forces | Motion depends on the combined effect, not just one force |
Tips for Students
✔ Gravity always acts downwards.
✔ Friction always opposes motion.
✔ Magnetic forces can either pull or push — check the poles.
✔ When unsure, draw arrows just like the teacher did.
✔ Complete the forces table logically, not by guessing.
For Parents
This is a common PSLE concept: interactions of multiple forces.
When students understand how to analyse each force separately, they gain confidence in solving MCQs accurately.
Practising such questions builds a strong foundation in Physics topics.