Definitions

Question 1

Parallax

Answer 1

A phenomenon which occurs as a result of having stereoscopic vision (2 eyes which see slightly different things).

Question 2

Special relativity

Answer 2

An object moving at a speed awhile is close to the speed of light is know as relativistic - no longer follows f=ma and therefore the mass increases.

Question 3

Newton

Answer 3

The force that causes a mass of 1kg to have an acceleration of 1ms^-2 in the direction of the force.

Question 4

Kinematics

Answer 4

The field of physics concerning the motion of bodies without any reference to the forces that cause the motion to happen.

Question 5

Dynamics

Answer 5

The field of physics concerned with the motion of bodies and the forces that cause the motion to happen.

Question 6

Homogenous

Answer 6

Every term in the equation must have the same physical dimensions (therefore the equivalent units).

Question 7

Velocity

Answer 7

The displacement per unit time. SI unit: m/s

Question 8

Vector

Answer 8

A quantity that had magnitude and direction.

Question 9

Strain

Answer 9

Fractional increase in length - x/l (no unit).

Question 10

Stress

Answer 10

Force applied per unit cross sectional area (F/A) measured in pa or N/m2

Question 11

Speed

Answer 11

Distance travelled per unit time

Question 12

Torque of a couple

Answer 12

One force x perpendicular distance between the forces.

Question 13

Scalar

Answer 13

A quantity that had magnitude only.

Question 14

Precise

Answer 14

Only a small variation between repeated readings.

Question 15

Moment

Answer 15

Force x perpendicular distance from pivot to line of action of force (Nm)

Question 16

Inelastic

Answer 16

A collision is inelastic if the momentum is conserved but some of the kinetic energy is transferred to other forms in the collision.

Question 17

Elastic

Answer 17

A collision is elastic if the momentum and the kinetic energy are conserved and no energy is transferred to other forms such as heat or sound.

Question 18

Density

Answer 18

Mass per unit volume (kg/m3)

Question 19

Displacement

Answer 19

The distance travelled in a particular direction - a vector quantity

Question 20

Young modulus

Answer 20

Stress/strain

Question 21

Centre of gravity

Answer 21

The point at which all the weight of an object appears to act.

Question 22

Accurate

Answer 22

A value is accurate if it is close to the true value.

Question 23

Acceleration

Answer 23

Rate of change of velocity (m/s)

Question 24

Spring constant

Answer 24

Characterised as the ‘stiffness’ of a spring.

Question 25

Current

Answer 25

Rate of flow of charge. SI unit: A

Question 26

Amplitude

Answer 26

The maximum displacement of a wave from its rest position