Test: Force & Pressure- 1 - Class 8 MCQ

• Force acting per unit area is termed as pressure.
• Pressure = force/ area on which it acts
• As area is in the denominator So, the smaller the area, larger the pressure on a surface for the same force.

Therefore, the correct answer is C: Pressure.

Muscular force is called contact force 

• Muscular force involves using muscles to push, pull, or lift objects.
• This type of force requires physical interaction with an object, meaning direct contact is necessary.
• Examples include lifting a book, kicking a ball, or pulling a rope.
• Contact forces, like muscular force, arise from physical interactions, distinguishing them from non-contact forces such as gravity or magnetism.

When a balloon is rubbed with a synthetic cloth, it becomes electrically charged due to friction. This charge creates an electrostatic force The balloon sticks to the wall because opposite charges attract.

When a load is suspended, the force of gravity pulls the load downward, stretching the spring. The spring resists this stretching by exerting an equal and opposite restoring force, as per elastic behavior.

• Gravitational force: Acts downward, pulling the rocket back to Earth.
• Frictional force (air resistance): Opposes the rocket's upward motion through the atmosphere.

These two forces act on the rocket immediately after it leaves the launch pad. Therefore Correct answer- Option B

The statement is False.

When you push a ball gently along a level surface, it does move, even if only slightly. The movement depends on factors like the force applied, friction, and the smoothness of the surface.

When a plastic bucket is held, the forces acting on it are balanced:

• Gravitational force pulls the bucket downward.
• The muscular force from the person holding the bucket pushes upward.

Since these forces are equal in magnitude and opposite in direction, they cancel each other out, preventing any change in the bucket's state of motion (i.e., it remains at rest). This is why the bucket does not move.

• Yes, magnets can exert a force on other magnets without touching them. This is because magnetic force is a non-contact force, meaning it can pull or push objects without physically touching them.
• Magnets have a magnetic field that surrounds them, with lines of force extending from the north pole to the south pole. 
• This field allows magnets to interact with each other, even when they're not touching.

• The athlete's legs exert a force downward against the ground.
• This downward force creates an equal and opposite reaction, propelling the athlete upward.
• The ground provides the necessary push to overcome gravity, allowing the jump to occur.
• The height achieved depends on the strength and technique of the jump.
• In summary, the athlete's force against the ground is what enables them to leap into the air.

Old NCERT

Correct Answer- Option D

When the bulb of the dropper is pressed, the air inside is forced out. Upon releasing the pressure, the atmospheric pressure acting on the surface of the water pushes the water into the dropper. This is because the pressure inside the dropper becomes lower than the pressure outside, causing water to rise in the dropper.