Test: Force - Primary 6 MCQ

The mass of an object remains unchanged when a force is applied. This is because force does not alter the material composition of the object; it only affects its state of motion or rest.

Balanced forces occur when two forces acting on an object are equal in size but opposite in direction, resulting in no change in the object's state of motion. This means the object remains at rest or continues to move at a constant velocity.

Friction between the tires and the road is essential for providing the necessary grip that allows the vehicle to accelerate, turn, and stop safely. Without sufficient friction, vehicles would skid and lose control, especially in adverse conditions.

Magnetic force is a non-contact force that can act at a distance without physical interaction between the magnet and the object. Unlike contact forces such as friction, normal force, and tension, magnetic force does not require direct contact.

Static friction reaches its maximum when an external force is applied to an object that is at rest but not enough to overcome that friction. Once the applied force exceeds static friction, the object begins to move, transitioning to kinetic friction.

The SI unit of force is the Newton (N). Named after Sir Isaac Newton, this unit quantifies the amount of force needed to accelerate a one-kilogram mass by one meter per second squared.

Smoother surfaces reduce the amount of interlocking between the surfaces, leading to a decrease in frictional force. This is why polished surfaces allow objects to slide more easily compared to rough surfaces.

Kinetic friction occurs when two surfaces slide against each other. It generally acts on moving objects and is typically less than static friction, which must be overcome to initiate movement.

Rolling friction occurs when an object rolls over a surface, such as a ball rolling on the ground. This type of friction is generally less than sliding friction, which makes rolling easier than sliding.

Lubricants are used in mechanical systems to reduce friction between moving parts. By creating a barrier between surfaces, lubricants help minimize wear and tear, enhance efficiency, and prolong the lifespan of machinery.

When a force is applied to an object at rest, it can overcome the inertia of the object, causing it to move. This principle is fundamental in understanding how forces initiate motion in everyday situations, such as pushing a chair or kicking a ball.

The area of contact does not significantly affect the magnitude of friction for most practical purposes. Friction primarily depends on the nature of the surfaces and the weight of the object pressing them together.

When a force is applied opposite to the direction of motion, it reduces the object's speed. This principle is utilized in braking systems of vehicles, where brakes exert a force opposite to the motion of the vehicle to slow it down.

A heavier object increases the normal force acting between two surfaces, thereby increasing friction. This is why it requires more effort to move heavier objects than lighter ones.

Gravitational force is a non-contact force that acts at a distance without physical contact between objects. In contrast, friction, tension, and normal force require direct contact between the interacting objects.

Gravitational force is the attractive force that pulls objects toward each other. For example, Earth’s gravitational force pulls objects toward its center, causing them to fall if dropped.

Rubbing hands together generates heat due to friction. This heat can warm your hands, which is particularly useful in cold weather. Friction converts kinetic energy from the rubbing motion into thermal energy.

Increasing the roughness of surfaces enhances the interlocking between them, thereby increasing friction. This is commonly seen in sports footwear with textured soles that improve grip on various surfaces.

Friction is the force that opposes the relative motion between two surfaces in contact. It acts in the opposite direction to the movement of the object, thereby slowing it down or bringing it to a stop.

A spring balance is a device used to measure force, typically in units of newtons. It operates on Hooke's law, where the force applied to the spring is proportional to the distance it stretches.