A.1: kinematics

Question 1

displacement

def

Answer 1

= a vector quantity and can be positive, negative or zero
x = final position - initial position

Question 2

position

def

Answer 2

= the placement of an object given in relation to a reference point

Question 3

distance

Answer 3

= s = length of the path followed
scalar quantity, can be only positive or zero, disregarding the direction of motion

Question 4

velocity

Answer 4

= rate of change of displacement, vector quantity (can be negative)

Question 5

speed

Answer 5

= rate of change of distance traveled, scalar quantity, absolute value of velocity

Question 6

acceleration

def, +a, -a?

Answer 6

• = rate of change of velocity, vector quantity
• +a ⇒ positive change in velocity, increasing velocity in the negative direction
• -a ⇒ negative change in velocity, decreasing velocity in the positive direction

Question 7

x(t) graph

steepness, v=const, v=0, sloped, inst v, ascending, descending

Answer 7

• m = x/t = v ⇒ steeper line → larger v → the faster the body is moving
• straight line ⇒ v = const
• v = 0 ⇒ line is parallel to the x-axis (time)
• sloped line ⇒ acceleration
• instantaneous velocity ⇒ determined with a tangent
• ascending graph ⇒ forward motion
• descending graph ⇒ backwards motion

Question 8

v(t)

steepness, a=cons, a=0, integral, average a, inst a

Answer 8

• m = vt = a ⇒ steeper line → larger a
• straight line ⇒ a = const
• a = 0 ⇒ line is parallel to the x-axis (time)
• integral of the graph (area under the line) = total displacement (above x-axis - +x, under - -x)
• average acceleration ⇒ uniform a to achieve the same Δv in the same amount of time (straight line from A to B)
• instantaneous acceleration ⇒ determined with a tangent

Question 9

average velocity on a graph

def, v(t), x(t)

Answer 9

• average velocity = the velocity it would take to travel a certain displacement over a certain time, if the velocity was constant (v = xt)
• a = 0 on a v(t) graph
• v=const on a x(t) graph

Question 10

velocity in projectile motion

inst, hor, vert

Answer 10

• instantaneous velocity has the tangent value of the trajectory
• velocity in the horizontal direction is constant
• velocity in the vertical direction travels in accordance with free fall

Question 11

uniform motion

formulas

Answer 11

v = Δx/t = st

v = const

Question 12

rate of change, gradient

Answer 12

m = Δy/Δx

Question 13

average velocity

formula, requirement

Answer 13

v = s/t
iff v = (v+u)/2

Question 14

uniform acceleration

formulas

Answer 14

a = Δv/Δt
v = u + at
x = (v^2 + u^2)/2a
x = ut + at^2/2

a = const

Question 15

projectile motion

formulas

Answer 15

• v^2 = vx^2+vy^2
• uy = usinα
• ux = ucosα
• R = uXt
• α = 45° ⇒ Rmax = u2/g
• α < 45° ⇒ R = u^2sin2α/g