Vectors

Definition of a vector.

A physical quantity that has both magnitude and direction.

Definition of a scalar.

A physical quantity that has magnitude only.

Definition of a resultant vector.

The single vector that has the same effect as the original vectors acting together.

Definition of distance.

The length of the path travelled.

Definition of displacement.

A change in position.

Definition of speed.

The rate of change of distance.

Definition of velocity.

The rate of change of position, or the rate of displacement, or the rate of change of displacement.

Definition of acceleration.

The rate of change of velocity.

Definition of weight.

The gravitational force the Earth exerts on any object on or near its surface.

Definition of normal force.

The perpendicular force exerted by a surface on an object in contact with it.

Definition of frictional force.

The force that opposes the motion of an object.

Definition of tension in a string or cable.

The tension in a string or cable is the same throughout the entire string or cable.

How to calculate the vertical component of a vector.

Multiply the magnitude of the vector by the cosine of the angle α, measured from the vertical.

How to calculate the horizontal component of a vector.

Multiply the magnitude of the vector by the cosine of the angle θ, measured from the horizontal.

How to calculate the parallel component of gravity on a slope.

Multiply the weight of the object by the sine of the angle of the slope.

How to calculate the perpendicular component of gravity on a slope.

Multiply the weight of the object by the cosine of the angle of the slope.

Definition of a Newton.

The force required to accelerate a 1 kilogram mass at 1 metre per second squared.

What are the two types of forces?

Contact forces and non-contact forces.

Give three examples of non-contact forces.

Gravitational force, magnetic force, and electrostatic force.

Give four examples of contact forces.

Normal force, frictional force, tension, and applied force.

What determines the magnitude of the gravitational force on an object?

The value of g (the gravitational field strength).

In which direction does the normal force always act?

Perpendicular to the surface.

What is the normal force equal to?

The total force which the object exerts on the surface.

Definition of mass.

The amount of matter that an object consists of.

Is mass a vector or a scalar quantity?

Mass is a scalar quantity.

What is the unit of mass?

The kilogram.

What is a free body diagram?

A diagram showing all of the forces that act on a single isolated body, unless otherwise stated.

What does the length of an arrow represent in a free body diagram?

The relative magnitude of the vector.

What must be used to represent the object in a free body diagram, rather than the object itself?

A dot.

State the sine rule.

Sin A / a = Sin B / b = Sin C / c.

Under what conditions can the sine rule be used?

When given two angles and one side, or two sides and an angle opposite one of the known sides.

State the cosine rule.

a squared equals b squared plus c squared minus 2bc cos A.

Under what conditions can the cosine rule be used?

When given three sides, or two sides and the enclosed angle.

Definition of static friction.

The frictional force that acts while an object is stationary, equal in magnitude to the applied force but opposite in direction.

What formula is used to calculate the maximum static friction?

F_fs(max) = μs × F_N.

Definition of kinetic friction.

The frictional force that acts once an object starts to move; it has constant magnitude and acts opposite to the direction of motion.

What formula is used to calculate kinetic friction?

F_fk = μk × F_N.

What is the relationship between the coefficient of kinetic friction and the coefficient of static friction?

The coefficient of kinetic friction is always less than the coefficient of static friction (μk < μs).