Posterous theme by Cory Watilo

1.10

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.

Scalar         

Vector                              

 distance

 velocity

 time

 displacement

 speed

 Force

 acceleration

 Weight

 money

 Momentum

Sausages  

 

Energy 

 

Mass 

 

 

 

Power

 

 

 

1.7 Plenary

 

·         1.7 determine the distance travelled from the area between a velocity-time graph and the time axis

 

Distance Time Graph

Velocity Time Graph

Gradient

 Speed

 Acceleration

Area under Graph

 No meaning

 Distance travelled

 

Plenary worksheet

Plenary worksheet

Tuesday, July 06, 2010

3:04 PM

Image001

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)     

Image004

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

1.6

Tuesday, July 06, 2010

3:04 PM

·         1.6 determine acceleration from the gradient of a velocity-time graph

 

     

 

<<moving-man_en.jar>>

   

 

 

http://phet.colorado.edu/en/simulation/moving-man

 

   

<div style="position: relative; width: 300px; height: 226px;">The Moving Man

Click to Run
</div>

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

Corrections to Questions on Acceleration

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