P 2. Kinematics Flashcards

1
Q

Is displacement vector or scalar?
and why?

A
  • Vector
  • Magnitude & direction
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2
Q

Is distance vector or scalar?
and why?

A
  • Scalar
  • No need to state its direction
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3
Q

Define speed?

A

The distance travelled in unit time

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4
Q

Define velocity?

A

The change of displacement per unit time

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5
Q

How to find average speed/velocity?

A

S = D/T

And that’s why it’s m/s O_o

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6
Q

Define acceleration?

A

The change of velocity per unit time

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7
Q

How to find average acceleration?

A

m/s² = m/s/s

that’s why it’s m/s² O_o

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8
Q

Acceleration formula in word form

A

Acceleration = Change in velocity/time taken

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9
Q

What are the 6 features in a displacement-time graph?
(and their definitions)

A
  1. Constant speed = Straight hill
  2. Stationary = Straight
  3. Negative direction = Going down
  4. Positive direction = Going up
  5. Acceleration = arc upwards
  6. Deceleration = arc downwards
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10
Q

What does the gradient in a displacement-time graph give u?

A

Velocity
(average speed)

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11
Q

What happens if u gain the negative gradient?

A

Negative velocity
(opposite direction)

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12
Q

What are the 5 features in a velocity-time graph?
(and their definitions)

A
  1. Constant acceleration = Straight hill up
  2. Constant speed = Straight
  3. Deceleration = Straight hill down
  4. No arcs
  5. There’s still positive/negative directions
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13
Q

What does the gradient give u in a velocity-time graph?

A

Acceleration
(m/s2)

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14
Q

What does the area under line give u in a velocity-time graph?

A

Displacement

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15
Q

What about area under their negative lines?

A

Negative displacement
(therefore ya minus when adding altogether)

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16
Q

Where do u find suvat equations?

A

…. in the damn data booklet.

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17
Q

Define s
(suvat)

A

Displacement

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18
Q

Define u
(suvat)

A

Initial velocity

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19
Q

Define v
(suvat)

A

Final velocity

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20
Q

Define a
(suvat)

A

Constant acceleration

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21
Q

Define t
(suvat)

22
Q

How to find initial velocity (u) in v-t graph?

A

The starting point of the “rise”
(Straight hill)

23
Q

How to find the final velocity (v) in v-t graph?

A

The ending point of the “rise”
(Straight hill)

24
Q

How do u derive V = u + at?
(4 steps)

A
  1. v-t graph (velocity time graph)
  2. Gradient = rise/run
  3. a = (v-u)/t
  4. Re-arrange to turn into the formula
    v = u + at
25
How do u derive S = ½ (u+v) t? (5 steps)
1. v-t graph (velocity time graph) 2. Displacement = average velocity x time 3. Average velocity = (u+v)/2 4. s = ((u+v)/2) x t 5. Re-arrange to turn into the formula s = ½ (u+v) x t
26
How do u derive S = ut + ½at2? (5 steps)
1. Combine: - S = ½(u+v) x t - V = u + at 2. S = ½ (u + {u + at}) x t 3. Do everything that it takes to get to the "formula" 4. S = 1/2 (u + at) x t S = ut + ½ at2
27
How do u derive v2 = u2 + 2as? (6 steps)
1. Use both equations: - v = u + at - s = ½ (u+v) x t 2. Find t of v = u + at 3. Sub that equation into second equation 4. s = ½ (u+v) x (v-u)/a 5. Do everything it takes to get to the "formula" 6. s = {(u+v) x (v-u)}/2a v2 = u2 + 2as
28
We have a problem, projectile motion. I'd wanna ask for help for this one but ahhh can I at least write summin brief notes?
- Say no air resistance or summin - Sometimes asked to find horizontal & vertical components (z sin/cos theta) - Use suvat for height or time of flight - Range = total horizontal distance use d = st - Down arc = parabowler - for acceleration (9.81), going up is **negative**, going down is **positive**
29
Define projectile? (3 things)
- Any body that is given an initial velocity - and then follows a path determined by - the **effect of gravity** on that object
30
Define trajectory?
Path followed by a projectile
31
What are the 2 motions consisting within projectile motion?
- Horizontal motion - Vertical motion
32
For the vertical motion y, what is it subject to when going up/down? How come? (1 each)
- Deceleration on the way up - Acceleration on the way down - Due to gravity
33
For the horizontal motion x, why does it remain constant? (2 points)
- Gravity isn't affected by it - Which acts only in vertical plane
34
Tell me about **horizontal** motion in projectile motion (Super optional)
- Not affected by gravity - Remains constant 1. Initial velocity = ucosθ 2. Acceleration = 0 3. Displacement at time t - Use S = ut + 1/2 at2 - We know a = 0 - And to find horizontal displacement = uxt - ∴ x = (ucosθ)t 4. Final velocity = same as initial velocity - Using v = u + at - a = 0 - vx = ux = ucosθ **dude just use ucosθ for horizontal component**
35
Tell me about **vertical** motion in projectile motion (Super optional)
- Subject to **deceleration going up** - **Acceleration going down** due to **gravity** 1. Initial velocity = usinθ 2. Acceleration = -g (initially & -9.81) 3. Displacement at time t - Use S = ut + 1/2 at2 - We know a = -g - Vertical displacement would be y = uyt - 1/2 gt2 - ∴ y = (usinθ)t - 1/2 gt2 4. Final velocity = initial minus gt - Using v = u + at - a = -g - vy = ux **dude just use usinθ for vertical component**
36
What are the 3 types of trajectories for projectile motion questions?
1. Normal Projectile Motion 2. Trajectory from a cliff 3. "Elevated" projectile motion
37
What isn't there for a typical projectile motion question?
Air resistance
38
A word for the shape of path created from a trajectory from a cliff?
Parabola
39
A "useful" tip for projectile motion questions?
Set out suvat symbols
40
For a projectile motion, what are the 2 things u must calculate? (Connection to basic physics)
- Horizontal components - Vertical components
41
What is the vertical component equivalent to? (suvat)
Initial velocity (u)
42
What's the final velocity always at for projectile motion?
... 0
43
How do u calculate the maximum height reached? (5 steps) (Normal Projectile motion)
1. Gain suvat from vertical motion part 2. Gain u, v & a 3. S = ? 4. Use V2 = u2 + 2as 5. Re-arrange for s
44
How do u calculate time of flight? (7 steps) (Normal Projectile motion)
1. Gain suvat from vertical motion part 2. Gain u, v & a 3. T = ? 4. Use V = u + at 5. Re-arrange for T 6. Always x2 the answer 7. As it's only for the first half of the flight
45
How do u calculate range? (4 steps) (Normal Projectile motion)
1. Gain "s", u & t of horizontal motion part 2. S = ? 3. Use s = d/t 4. Re-arrange for d
46
How do u calculate time taken until it hits? (5 steps) (Trajectory from a cliff)
1. Gain suvat from vertical motion part 2. Gain s, u, & a 3. T = ? 4. Use S = ut + ½at2 5. Re-arrange for T
47
How do u calculate the range? (4 steps... hollon) (Trajectory from a cliff)
1. Gain "s", u & t of horizontal motion part 2. S = ? 3. Use s = d/t 4. Re-arrange for d
48
How do u calculate magnitude and direction of resultant velocity? (7 steps) (Trajectory from a cliff)
1. Gain suvat from vertical motion part 2. Gain s, u, a & t 3. The shape is like an upside-down right-angled triangle 4. Use v = u + at 5. Final velocity = the "opposite" 6. Pythagoras theorem for resultant velocity 7. Trigonometry for direction of resultant velocity
49
How to answer projectile motion of an elevated trajectory? (check-uppp) (still imp too)
**3 (Elevated trajectory):** 1. Basketball, fadeaway shot, how long it takes for ball to hit ground? - So this is just purely vertical motion part - Find vertical component - Afterwards, hope that it states how high it was released - Then apparently that height has gotta be negative (could be similar to how going up must be -g) - Use equation S = ut + 1/2 at2 - And then, u actually just re-arrange to make it into ax2 + bx + c - Gain values of t by factorising (or use calculator B|) - Whatever answer u get, obviously it won't be the negative (Don't get confused, keep trying to figure it out, took me a while from the exemplar question)
50
Albert Einstein said that u learn from starting from the first principles
Revamped successfully?
51
Unsure about elevated trajectory However, past papers are a must
Correct