CIE IGCSE Physics Flashcards

Speed and Motion

• Speed is calculated as distance divided by time.
• A distance-time graph displays a horizontal line when an object is at rest.
• A constant speed results in a slanted line on a distance-time graph.
• A curved line indicates changing speed in a distance-time graph.
• In speed-time graphs, the area under the graph represents the distance traveled during constant acceleration.
• A speed-time graph shows a positive gradient for accelerating bodies and a negative gradient for decelerating bodies.
• Speed is a scalar quantity, while velocity is a vector with both magnitude and direction.

Acceleration

• Acceleration (a) is defined as the change in velocity (∆v) divided by time (t).
• On a distance-time graph, speed is represented by the gradient of the line.
• Acceleration on a speed-time graph is also indicated by the gradient.
• A straight line with a positive gradient on a speed-time graph indicates constant acceleration.
• A curved line with a positive gradient suggests changing acceleration.
• Deceleration is synonymous with negative acceleration.

Mass and Weight

• Mass refers to the number of particles in a body.
• Weight is a gravitational force acting on a mass.
• The difference between mass and weight lies in gravitational field strength affecting weight; mass remains constant.
• Weight (W) is calculated using the formula W = m × g, where g is the acceleration due to gravity.
• Comparison of weights using a balance scales involves placing weights on either side and determining which side is heavier.

Density

• Density (ρ) is calculated as mass (m) multiplied by volume (V).
• To find the density of a liquid or regular solid, weigh the object, measure the volume, and apply the density formula (ρ = m/V).
• The method of displacement is used for irregularly shaped solids: submerge the solid in water to measure the volume displaced and then find density.
• An object will float if its density is less than that of the liquid it's placed in.

Forces and Motion

• A force can alter the size and shape of a body.
• Forces can provoke changes in speed, direction, or shape of an object.
• When forces act along the same line, the resultant force is the sum of the individual forces.
• A body with no resultant force will either remain still or move at a constant speed in a straight line.
• Friction is the force between two surfaces that hinders motion and generates heat.
• Air resistance is a specific type of friction experienced by objects moving through the air.

Hooke's Law

• Hooke's Law states that the force (F) required to extend or compress a spring is proportional to the distance (e) it is stretched or compressed.
• The relationship in Hooke's Law is expressed as F = k × e, where k is the spring constant.
• The limit of proportionality refers to the point on an extension-load graph beyond which the relationship no longer remains linear and begins to curve.