1.12 Plenary
14 September 2010
15:14
Tell the person next to you…
When does 2 + 2 = 4?
When does 2 + 2 = 0?
Answers below...
1.10
Tuesday, July 06, 2010
3:04 PM
· 1.10 distinguish between vector and scalar quantities
Sort the following into the table below:
distance, velocity, time, displacement, speed, acceleration, money (baht), energy, force, power, momentum, mass, weight, sausages.
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Scalar |
Vector |
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distance |
velocity |
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time |
displacement |
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speed |
Force |
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acceleration |
Weight |
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money |
Momentum |
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Sausages |
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Energy |
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Mass |
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Power |
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· 1.7 determine the distance travelled from the area between a velocity-time graph and the time axis
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Distance Time Graph |
Velocity Time Graph |
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Gradient |
Speed |
Acceleration |
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Area under Graph |
No meaning |
Distance travelled |
Plenary worksheet
Tuesday, July 06, 2010
3:04 PM
Question 1
a) 12 seconds
b) d=100m, t=12s, v=d/t, v=100/12, v=8.3m/s
c) A- the runner is accelerating, B – the runner is at a constant speed, C – The runner is decelerating, D – The runner has topped.
d) The speed is greatest in A, because the runner is accelerating the most.
e) 124m
Question 2
a) 1.5m/s
b) 1s
c) v=1.5m/s, t=1s, a=∆v/∆t, a=1.5/1, a= 1.5m/s2
d) d=1/2bxh, d=0.5x1.5, d=0.75m
e) d=1/2bxh, d=1x1.5, d=1.5m
Question 3
a)
b) 35s
c) 10m/s
d) v=15m, t=15s, a=∆v/∆t, a=15/15, a= 1m/s2
e) v=20m/s, t=20s, d=s x t, d=20x20, d=400m
1.6
Tuesday, July 06, 2010
3:04 PM
· 1.6 determine acceleration from the gradient of a velocity-time graph
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From your Maths lessons you know that:
Gradient = ∆y / ∆x
But for a velocity time graph velocity is on the y axis and time is on the x axis…
Gradient = ∆y / ∆x = ∆v / ∆t
Look familiar?
Gradient = ∆y / ∆x = ∆v / ∆t = a
1. A car changes its velocity by 30 m/s in 5 seconds, what is the acceleration of the car?
v=30m/s
t=5s
a=∆v/∆t
a=30/5
a=6m/s2
2. A bike starts from rest and accelerates to 20 m/s over a period of 6 seconds. What is the acceleration of the car?
v=20m/s
t=6s
a=∆v/∆t
a=20/6
a=3.33m/s2
3. A man moving at 2 m/s accelerates at a rate of 3 m/s2 for 2.5 seconds. What is the new velocity of the man?
a=3m/s2
t=2.5s
ax∆t=∆v
3x2.5=∆v
v=7.5m/s
a=v-u/∆t
3=v-2/2.5
V=9.5m/s
4. A car decelerates from 60 m/s to 20 m/s at a rate of -5 m/s2. How long does this deceleration take the car?
v= -40m/s
a= -5m/s2
t=∆v x a
t=-40x-5
t=200s
a=v-u/∆t
-5=20-60/t
t=8s