Definitions

Question 1

Scaler + examples

Answer 1

Magnitude without direction

e.g. length, area, volume, distance, temperature, energy, work, power, electrical potential, charge, time

Question 2

vector

Answer 2

A quantity that has (both) magnitude / size and direction

e.g. Displacement, velocity,
acceleration, momentum, force (lift, drag,
thrust, weight), field(s), a.c. voltage, current
(when calculating fields only)

Question 3

define displacement

Answer 3

(net) distance moved in a particular direction

Question 4

define instantaneous speed

Answer 4

speed measured between two point a very small time apart

Question 5

define average speed

Answer 5

distance covered/time taken

Question 6

define velocity

Answer 6

speed in a given direction

Question 7

define acceleration

Answer 7

the gradient of a velocity vs time graph ( change in velocity/time taken)

Question 8

define a newton

Answer 8

The (net) force which gives a mass of 1 kg an acceleration of 1ms^-2

Question 9

define and apply the moment of force

Answer 9

moment = force x perpendicular distance from pivot/ axis/point

Question 10

define and apply the torque of a couple

Answer 10

one of forces x perpendicular distance (between forces) (Not force x perpendicular distance )

Question 11

define thinking distance

Answer 11

the distance traveled (by the car) from when the driver sees a problem and the breaks are applied

Question 12

define braking distance

Answer 12

Distance traveled (by the car) whilst the brakes are applied and the car stops(wtte)

Question 13

define stopping distance

Answer 13

Thinking distance +
braking distance

Question 14

define work done by a force

Answer 14

work done = force x distance moved /
travelled in the direction of the force

Question 15

define joule

Answer 15

Energy required to move a weight of 1N
(through) a distance of 1 m

Question 16

define power as the rate of work done

Answer 16

power = work (done)/time or power =
energy/time or power = rate of work done

Question 17

define a watt

Answer 17

Power required to move 1N through a
distance of 1m in 1 sec (Rate of doing work)

Question 18

define and use the terms stress

Answer 18

Stress = force/(cross-sectional) area

Question 19

define and use the term strain

Answer 19

Strain = extension/original length

Question 20

define and use the term young modulus

Answer 20

Young modulus = stress/strain / Young
modulus is equal to the gradient from stress-strain graph (in the linear region)

Question 21

define and use the term ultimate tensile strength(breaking stress)

Answer 21

Ultimate tensile strength = Maximum stress
material can withstand (before fracture

Question 22

define the term elastic deformation of a material

Answer 22

Elastic: extension (or compression)
(as long as elastic limit is not exceeded)

Question 23

define the term plastic deformation of a material

Answer 23

Plastic: Material does not return to original
length / shape/ size (is permanently
deformed / longer) when the force / stress is
removed