Balanced and Unbalanced Forces - Worksheet | Printable and ... - Free Printable

Let's solve both questions step by step.

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Q.7: Which of the following is *not* an example of unbalanced forces?

We need to identify which scenario does not involve unbalanced forces.

Recall:
- Unbalanced forces cause a change in motion (acceleration, starting, stopping, changing direction).
- Balanced forces result in no change in motion (object at rest or moving at constant velocity).

Now analyze each option:

#### a) A rising balloon
- The balloon is rising, meaning it's accelerating upward.
- This implies upward force > downward force (gravity) → Unbalanced forces
✔ Unbalanced

#### b) Kicking a football
- When you kick a football, it starts moving from rest → acceleration.
- Force applied changes its motion → Unbalanced forces
✔ Unbalanced

#### c) A boy standing still
- The boy is at rest, not moving.
- Gravity pulls him down, but the ground pushes up with equal normal force.
- These forces are equal and opposite → Balanced forces
✘ Not unbalanced → This is the correct answer

#### d) An airplane taking off
- The plane accelerates from rest to high speed → changing motion.
- Thrust > drag and lift > weight initially → Unbalanced forces
✔ Unbalanced

✔ So, the one that is not an example of unbalanced forces is:

> c) A boy standing still

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✔ Answer to Q.7: c)

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Q.8: What is the magnitude of the net force?

Given forces on a block:
- One force of 7 N to the left (←)
- Two forces to the right: 3 N and 4 N

So, total force to the right = 3 N + 4 N = 7 N

Total force to the left = 7 N

Net force = Right - Left = 7 N - 7 N = 0 N

Even though there are multiple forces, they cancel out completely.

✔ Net force = 0 N

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✔ Answer to Q.8: b) 0 N

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✔ Final Answers:

- Q.7: c) A boy standing still
- Q.8: b) 0 N