Force: Balanced and Unbalanced MCQs
Practice Force: Balanced and Unbalanced multiple-choice questions from How Forces Affect Motion (Class 9 Science) - tap an answer for instant feedback and a step-by-step solution. Practice the full set free on the RankByte app.
Force: Balanced and UnbalancedQuiz - Solve & Score
Q1. Which is a non-contact force?
- A.gravitational force between the Earth and a falling apple
- B.friction between tyres and road
- C.the push of a hand on a door
- D.tension in a rope pulling a cart
Answer: A. gravitational force between the Earth and a falling apple
NCERT fact (physics, chapter 'How Forces Affect Motion'): Gravitation acts at a distance without contact - a non-contact force. Why option A fits - Correct. Distractor analysis: option B) 'friction between tyres and road' misses the point - Friction is a contact force; option C) 'the push of a hand on a door' is wrong because A push by contact is a contact force. Final answer - A) gravitational force between the Earth and a falling apple.
Q2. A force can change all of the following EXCEPT one. Which CANNOT be changed by a force alone in the way described?
- A.the chemical identity of a substance
- B.the speed of a moving body
- C.the direction of motion
- D.the shape of a soft object
Answer: A. the chemical identity of a substance
NCERT fact (physics, chapter 'How Forces Affect Motion'): Forces change motion, shape or direction, not the chemical identity of matter. Why option A fits - Correct. Distractor analysis: option B) 'the speed of a moving body' is incorrect: A force can change speed; option C) 'the direction of motion' misses the point - A force can change direction of motion. Final answer - A) the chemical identity of a substance.
Q3. Which observation shows that force is a vector quantity?
- A.the effect of a force depends on its direction as well as its size
- B.force has only magnitude
- C.force never changes motion
- D.force is measured in kilograms
Answer: A. the effect of a force depends on its direction as well as its size
Which principle settles this? A quantity needing both magnitude and direction is a vector; force qualifies. Does that line up with one of the options? Yes - Correct. And the rest? option B) 'force has only magnitude' doesn't hold - If it had only magnitude it would be a scalar; it is a vector; option C) 'force never changes motion' misses the point - Force does change motion; this is unrelated to being a vector. Pick: A) the effect of a force depends on its direction as well as its size.
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