Forces and Motion

Question 1

Speed equation

Answer 1

(m/s) = distance (m) / time (s)
s = d / t

Question 2

Speed vs Velocity

Answer 2

Speed is scalar (only magnitude)
Velocity is a vector (magnitude and direction)

Question 3

Scalar examples

Answer 3

speed
temperature
energy

Question 4

Vector examples

Answer 4

velocity
force
acceleration

Question 5

Acceleration equation

Answer 5

(m/s2) = change in velocity(m/s) / time (s)
a = v-u / t

Question 6

velocity time graphs

Answer 6

area under graph = distance travelled
x axis = time
y axis = velocity

Question 7

Distance vs Displacement

Answer 7

Distance is a measurement of the total path travelled.
Displacement is the straight line measurement between the starting and finishing point.

Question 8

Final speed equation (v2)

Answer 8

initial speed (u2) + 2 x acceleration x displacement
v2 = u2 +2as

Question 9

Forces

Answer 9

Gravity
Tension
Friction
Air resistance
Reaction Force
Thrust

Question 10

Force of gravity (weight)

Answer 10

pulls an object towards the centre of a large mass

Question 11

Tension

Answer 11

a force in a rope or cable being pulled

Question 12

Friction

Answer 12

a counter force caused when two objects rub together

Question 13

Air Resistance

Answer 13

a counter force produced whan an object travels through air

Question 14

Reaction force / normal

Answer 14

the upward force from a surface to counter weight

Question 15

Thrust

Answer 15

a pushing force (e.g. by an engine/rocket)

Question 16

Balanced Forces

Answer 16

Stationary
Constant speed in same direction

Question 17

Unbalanced Forces

Answer 17

Speed up
Slow down
Change direction
Change shape

Question 18

Force equation (N)

Answer 18

Mass (kg) x Acceleration (m/s2)
F = M*A

Question 19

Weight equation (N)

Answer 19

Mass (kg) x Gravitational field strength (N/Kg)
W = m*g

Question 20

Terminal velocity

Answer 20

• Start, air resistance 0, acceleration downwards
• As speed increases, air resistance also increases
• Eventually, forces will balance, constant speed. (Terminal Velocity)
• When opens parachute, air resistance increases, slows down
• As slows down, air resistance decreases, until balances with weight
• New, lower, terminal velocity.

Question 21

Stopping distance

Answer 21

thinking distance + breaking distance

Question 22

Factors affecting thinking distance

Answer 22

alcohol/drugs
age
tiredness
distracted

Question 23

Factors affecting breaking distance

Answer 23

• condition of brakes
• condition of tyres
• condition of road (wet / icy)
• speed of car
• mass of car

Question 24

Hooke’s Law

Answer 24

• Extension directly proportional to Force until elastic limit
• When load is removed, the material springs back to its original length
• If the spring excceeds the elastic limit, plastic deformation will occur

Question 25

Plastic vs Elastic deformation

Answer 25

Elastic - object WILL return to its shape
Plastic - object WILL NOT return to its shape

Question 26

Materials which not obey hooke’s law

Answer 26

rubber

Question 27

Force vs. Extension graph

Answer 27

Force (y axis)
Extension (x axis)