Lecture 1: Kinematics

Question 1

what is velocity?

Answer 1

describes how quickly an object gets from one place to another
it is a vector - both magnitude and direction

Question 2

v = Δx/Δt or Δx = vΔt

Answer 2

v is velocity vector, Δx is displacement vector, Δt is time interval
Δx = xf - xi

Question 3

what is relative velocity?

Answer 3

the difference between two velocities

Question 4

Steps to solve a question

Answer 4

1. highlight important information
2. draw a sketch of the scenario
3. work out what values you have
4. put these into a formula
5. solve

Question 5

what is acceleration?
basic equation?

Answer 5

it is change in velocity over time
a =Δv /Δt

Question 6

characteristics of acceleration

Answer 6

1. it’s a vector quantity
2. it can be positive or negative
3. can have acceleration without changing speed

Question 7

what are two other equations?
one with no change in acceleration
other with a known acceleration

Answer 7

vf = vi + at
d =1/2 at^2

Question 8

what is average velocity?
equations?

Answer 8

d=vt
assumes that there is no acceleration
v(av) = (vi + vf) - constant acceleration
v (av) =(vi+vf)/2

Question 9

change in displacement under constant acceleration formula

Answer 9

d = v(av)t = 1/2 (vi + vf)t = 1/2(vi + vi + at)t
= vit + 1/2at^2
OR
d= 1/2at^ 2 -If starting @ rest

Question 10

what is the acceleration due to gravity?

Answer 10

all objects freely falling towards earth experience 9.81 m/s^2 or 10m/s^2 acceleration towards earth at sea level on surface of earth
this quantity changes with altitude

Question 11

features of projectile motion

Answer 11

at maximum height it is halfway through horizontal distance and velocity is 0m/s
it is symmetrical around max height

Question 12

what does independence of motion in 2D mean?

Answer 12

horizontal and vertical components of motion in 2D do not effect each other (i.e. they are independent)
horizontal velocity does not change
vertical velocity is affected by gravity