Answer key

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Last edited 26 days ago by Learn LoopHQ.

Chapter: 04. Force

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Force can change the shape and size of an object, such as when you press a balloon.

Sir Isaac Newton is also credited with inventing the mirror telescope.

Kabaddi players rub their hands with soil to increase the friction and roughness of their hands, which provides a better and firmer grip on their opponents.

A rolling ball eventually comes to rest on the ground due to the force of friction acting between the ball and the ground, which opposes its motion.

No, we cannot see force directly, but we can observe its effects.

The three types of non-contact forces are gravitational force, magnetic force, and electrostatic force.

Force is commonly defined as a push or a pull that acts on an object.

Kicking a ball is an example of applying force as a push.

Vehicles are fitted with wheels because rolling friction is much less than sliding friction, making it easier to move objects with wheels.

It is difficult to drive on wet roads during rains because water acts as a lubricant, significantly reducing the friction between the tires and the road surface.

When you try to push a heavy table but it doesn’t move, static friction is in play, preventing its motion.

Buses and trucks have heavier and wider tires to distribute their heavy loads over a larger area, providing better grip, stability, and reducing wear.

The experiment involves comparing the force needed to pull a wooden block across a table (sliding) versus pulling it with cylindrical rods or pencils placed underneath (rolling), observing that less force is required in the latter case.

If the moisture is more, the friction between the ball and the ground decreases, making it difficult to spin the ball.

Friction between the ground and our feet or footwear allows us to walk by providing the necessary grip to push against the ground.

Pulling a suitcase towards yourself is an example of applying force as a pull.

Sir Isaac Newton formulated the universal law of gravitation.

Strong winds and storms are natural things that exert force.

The force of friction is larger between two rough surfaces and smaller between two smooth surfaces.

Forest fires can occur naturally because friction between dry branches rubbing against each other can generate enough heat to cause them to catch fire.

Sliding friction is experienced when a flat block is moved over a flat surface.

A contact force is applied to an object by another object that is in direct physical contact with it.

One major disadvantage of friction in machinery is that it causes wear and tear in parts and produces heat, reducing efficiency.

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