physics types of motion

Force of friction

Acts on an object in a direction opposite to the direction of its motion.

Magnetic force

Like poles of a magnet repel each other, while unlike poles attract each other.

Electrostatic force

Like charges repel each other, while unlike charges attract each other.

Gravitational force

The Earth attracts objects towards itself.

Buoyant force

Exerted by liquid in an upward direction on an object placed in it.

SI unit of force

The newton (N), which specifies both magnitude and direction.

Magnitude of force

Expresses the strength of the force.

Effect of force

If either the magnitude or direction, or both, of a force applied on an object changes, the effect of the force also changes.

Measuring the magnitude of a force

A spring balance can be used to measure not just the weight of an object but the magnitude of the force in general.

Spring balance

Used to measure the force applied, particularly the weight of objects due to gravitational force; it measures how much a spring is stretched or compressed.

Smallest forces felt

The smallest forces we can directly feel are of the order of millinewtons ( ext{10}^{-3} N), such as a light touch.

Smallest measurable forces

Scientists can measure forces down to yoctonewtons ( ext{10}^{-24} N) in specialized experiments.

Balanced forces

Two forces that are equal in magnitude but opposite in direction.

Unbalanced forces

Forces that are not equal in magnitude or opposite in direction, causing movement in the direction of the larger force.

Net force

When the forces applied on an object are unbalanced, a non-zero net force acts on the object.

Magnitude of net force

The net force is equal to the difference between the magnitudes of two opposite forces, with the direction along the larger force.