9th Grade IGCSE Combined Science - Force and Motion

Flashcards covering key concepts in force, motion, mass, weight, density, and pressure based on the IGCSE Combined Science 9 syllabus.

What is speed?

Distance travelled by an object per unit time.

What two measurements are needed to determine average speed?

Total distance travelled between two points and the total time taken to travel between these points.

What are the common units for speed?

Metres per second (m/s), kilometres per hour (km/h), miles per hour (mph)

How do you solve a speed problem?

Write down what you know and what you want to know, choose the appropriate equation, substitute values with units, and perform the calculations with units.

How does a distance-time graph show an object's speed?

The graph slopes up gently, the graph becomes steeper, the graph is flat (horizontal).

What is acceleration?

The rate of change of velocity.

When does acceleration occur even if speed is constant?

When an object moves in a circular path at a constant speed, it is still accelerating because the direction of its velocity is changing.

What is velocity?

Velocity is the speed in combination with the direction of motion of an object.

What is the formula for calculating acceleration?

Av/t

What are the units for acceleration?

M/s², km/s², mi/hr/s

What does a negative slope on an acceleration-time graph mean?

A negative slope on an acceleration-time graph indicates deceleration.

Name common types of forces.

Muscular force, frictional force, gravitational force, electrostatic force, magnetic force.

What is the difference between a scalar and vector quantity?

A scalar quantity has only magnitude, while a vector quantity has both magnitude and direction.

Give examples of Scalar Quantities

Length, area, volume, speed, mass, density, pressure, temperature, energy, entropy, work, power.

Give examples of Vector Quantities

Displacement, velocity, acceleration, momentum, force, lift, drag, thrust, weight.

What is motion?

The action of changing location or position.

What is translation?

Motion along a line or a curve.

Name different types of motion.

Linear motion, projectile motion, circular motion, rotary motion, oscillatory motion.

What is centripetal force?

Force acting towards the center

What factors affect centripetal force?

The mass of the object increases, the speed of the object increases, the radius of the orbit decreases.

What is free fall?

An object moving under the influence of gravitational force only.

What is the formula to calculate velocity in free fall?

v = gt

When can air resistance be ignored in free fall calculations?

Air resistance is negligible for heavier objects that fall near the surface of the Earth.

How do rising objects behave in free fall?

Rising objects decelerate at the same rate that falling objects accelerate.

What is air resistance?

A resistance force caused by air molecules opposing the motion of an object as it moves through the air.

List contact forces.

Applied force, spring force, drag force, frictional force, normal force.

List non-contact forces.

Magnetic force, electric force, gravitational force.

What is force?

A push or pull on an object, it is a vector quantity.

What is the unit for force?

Newton (N)

What is a resultant force?

A single force which can replace a set of forces acting on an object, having the same effect.

What's the difference between weight and mass?

Mass is the amount of matter in an object, while weight is a measure of the gravitational force.

How do mass and weight differ in terms of constancy?

Mass is constant, weight is variable.

What is the formula for weight?

W = mg, where g is the acceleration due to gravity.

What is the formula for Force, Mass & Acceleration?

density = mass/volume

What is the formula of Pressure?

p = F/A

What is density?

The amount of mass in a volume.

What are common units for density?

grams per cubic centimeter (g/cm3) or kilograms per cubic meter (kg/m3)

what is the equation for Density.

Density = mass / volume

How do you calculate Pressure?

Force / area

What are the units of pressure?

Pressure is measured in Newtons per square metre (N/m2) or Pascals (Pa).

how do you control preassure?

Increase the pressure by reducing the area. Reduce the pressure by increasing the area.

How does air pressure change with altitude?

Air pressure gets less as you rise up through the atmosphere.

How is atmospheric pressure measured?

By using a barometer.

How does pressure change in liquids?

Pressure increases with depth, acts in all directions, and depends on the density of the liquid.

What is the formula for calculating pressure in a liquid?

Pressure = ρgh, where ρ is density, g is acceleration due to gravity, and h is height of liquid.

How does a barometer measure air preassure.

Air pressure will push mercury up the tube.

How does pressure act in a liquid?

Pressure acts in all diection in a liquid.

How does weight and area, afect preassure.

Weight/ Area.

What is the volume formula.

m/v = d.

When you are drawing acceleration, what is important to note.

The slope is steep, Acceleration.