Exploring Forces
Short Questions
1. What is a force?
Answer:- A push or pull on an object.
2.What is muscular force?
Answer:- Force caused by muscle action.
3.What is friction?
Answer:- A force that opposes motion between surfaces.
4.What is a contact force?
Answer:- A force that requires physical contact.
5.What is a non-contact force?
Answer:- A force that acts without physical contact.
6.What is magnetic force?
Answer:- Force exerted by magnets on magnetic materials.
7.What is electrostatic force?
Answer:- Force between charged objects.
8.What is gravitational force?
Answer:- Force with which Earth pulls objects downward.
9.What is weight?
Answer:- Gravitational force on an object, measured in newtons.
10.What is buoyant force?
Answer:- Upward force by a liquid on an object.
11.What unit is used to measure force?
Answer:- Newton (N).
12.Why does a ball stop rolling on its own?
Answer:- Due to friction.
13.What happens when like poles of magnets are brought close?
Answer:- They repel each other.
14.What is Archimedes’ Principle?
Answer:- An object in a liquid experiences an upward force equal to the weight of the liquid displaced.
15. Does mass change from place to place?
Answer:- No, mass remains the same.
Long Questions
1. Why does it feel harder to pedal a bicycle uphill than on flat ground?
Answer:- Uphill pedaling requires more force to overcome gravity. Friction also increases on a slope.
2. Why is it easier to slip on a wet surface?
Answer:- Wet surfaces reduce friction, making them slippery. Less grip causes easier slipping.
3. Why do we feel ‘light’ at the top of a swing?
Answer:- At the top, gravity and motion briefly balance, reducing the feeling of weight. You feel like floating.
4. How does friction affect a rolling ball on different surfaces?
Answer:- Rough surfaces increase friction, stopping the ball sooner. Smooth surfaces have less friction, so the ball rolls farther.
5. What happens when two charged balloons are brought close?
Answer:- If similarly charged, they repel each other. If oppositely charged, they attract.
6. Why does a wooden block float but a coin sinks in water?
Answer:- A wooden block is less dense than water, so buoyant force makes it float. A coin is denser, so it sinks.
7. What forces act on a ball thrown upwards?
Answer:- During upward motion, gravitational force acts downward, slowing it. At the top and downward, gravity pulls it down.
8. How can you make a ball stop before or after a point on a horizontal surface?
Answer:- Increase friction (rough surface) to stop it before. Decrease friction (smooth surface) to stop it after.
9. How does a spring balance measure weight?
Answer:- It uses a spring that stretches under an object’s weight. The stretch is measured in newtons on a scale.
10. Why do some objects float while others sink in water?
Answer:- Objects float if buoyant force equals their weight. They sink if their weight is greater than buoyant force.
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