Forces in Action Practice Flashcards

Vocabulary-style flashcards covering types of forces, friction, weight vs. mass, buoyancy, terminal speed, and balanced/unbalanced forces based on the Year 7 Science Study Notes.

Forces

Pushes or pulls that can change an object's motion, shape, or speed.

Contact Forces

Forces that require physical contact between two objects to occur.

Non-Contact Forces

Forces that can act on an object without any physical contact through fields such as magnetic, gravitational, or electric fields.

Frictional Force

A contact force that opposes motion when two surfaces are in contact.

Traction

A type of friction representing the grip or adhesion between a surface and an object, such as a tyre on a road.

Buoyancy (Upthrust)

The upward force exerted by a fluid (liquid or gas) on an object placed in it.

Air Resistance (Drag)

A type of friction that opposes the motion of an object through air.

Water Resistance (Drag)

A type of friction that opposes the motion of an object through water.

Normal Force

The support force exerted by a surface on an object resting on it, such as a book on a table.

Gravitational Force

The force of attraction between any two objects with mass, such as the Earth pulling objects towards its center.

Magnetic Force

The force of attraction or repulsion between magnets or magnetic materials.

Electrostatic Force

The force of attraction or repulsion between electrically charged objects.

Friction

A contact force that resists the sliding or rolling of one surface over another, always acting in the direction opposite to the motion.

Lubricants

Substances like oil, grease, or water that create a slippery layer between surfaces to reduce friction and prevent wear.

Ball Bearings

Components used to replace sliding contact with rolling contact to decrease friction.

Streamlining

Giving an object a smooth, rounded shape to reduce the friction from fluids like air or water resistance.

Mass

The amount of stuff or matter in an object, measured in kilograms ($kg$); it does not change regardless of location.

Weight

The force of gravity acting on an object's mass, measured in Newtons ($N$); it changes depending on the gravitational field strength.

Weight Formula

$$Weight (N) = Mass (kg) \times \text{Gravitational Field Strength} (N/kg)$$

Gravitational Field Strength (Earth)

Approximately $10\text{ N/kg}$, meaning Earth's gravity pulls with a force of $10\text{ N}$ for every $1\text{ kg}$ of mass.

Gravitational Field Strength (Mars)

Given as $4\text{ N/kg}$.

Terminal Speed (Velocity)

The constant maximum speed reached by a falling object when the upward force of air resistance is exactly equal to the downward force of weight.

Balanced Forces

Forces equal in size and opposite in direction that cancel each other out, resulting in a net force of zero and no change in motion.

Unbalanced Forces

Forces that do not cancel out completely, resulting in a non-zero net force which causes an object to accelerate.

Net Force Calculation

Adding forces acting in the same direction and subtracting forces acting in opposite directions; the final direction is that of the larger force.