Linear Motion Flashcards
1
Q
scalar quantity
A
has only a magnitude - no direction in space
2
Q
vector quantity
A
has both magnitude and direction
3
Q
displacement
A
- the distance moved in a particular direction
- symbol = s
- unit = m
4
Q
velocity
A
- the rate of change of displacement with respect to time
- symbol = u or v
- unit = m/s
(v = s/t)
5
Q
average velocity
A
- the distance travelled divided by the time taken
- s/t
- u+v/2
6
Q
constant velocity
A
- the object does not speed up, slow down or change direction
- u = v
7
Q
measuring velocity with a ticker tape
A
- measure 11 dots (10 spaces)
- times by 0.05 = v in m/s
- or % by 100 × 5 (cm to metres)
8
Q
acceleration
A
- the rate of change of velocity with respect to time
- symbol = a
- unit = m/s²
- v-u/2
9
Q
derivation of v = u + at
A
1) use acceleration formula
2) multiply both sides by t
10
Q
derivation of s = ut + 1/2 at²
A
1) let two equations for average velocity equal each other s/t = u + v/2
2) multiply both sides by t
3) substitute (u + at) for v
4) simplify into 1 line
5) divide equation by 2
11
Q
derivation of v² = u² + 2as
A
1) start with equation 1 - v = u + at
2) square both sides
3) multiply out brackets
4) take out 2a ; 2a( ut + 1/2 at²)
5 replace ( ut + 1/2 at²) with s
