Author Topic: Physics Help HERE ONLY !!  (Read 81546 times)

holtadit

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Re: Physics Help HERE ONLY !!
« Reply #855 on: December 27, 2009, 11:38:05 am »
The speed of a cyclist reduces uniformly from 2.5 m/s to 1.0 m/s in 12 s.

(a) Calculate the deceleration of the cyclist.

deceleration = ..................................

(b) Calculate the distance travelled by the cyclist in this time.

distance = ..................................

How would u do the (b) part ? The examiners report says that it should be average speed multiplied time... but how do u get the average speed ? Please show your workings !

Offline astarmathsandphysics

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Re: Physics Help HERE ONLY !!
« Reply #856 on: December 27, 2009, 01:40:54 pm »
Average speed is (u+v)/2=(2.5+10)/2=6.25

Offline saleemsamer

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Re: Physics Help HERE ONLY !!
« Reply #857 on: December 27, 2009, 03:05:09 pm »
Average speed is (u+v)/2=(2.5+10)/2=6.25
it is 1.0 not 10

Offline astarmathsandphysics

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Re: Physics Help HERE ONLY !!
« Reply #858 on: December 27, 2009, 03:36:45 pm »
Shoot me

\skldnb c1juk

sHOOT ME AGAIN!!!!!!!!!!!!

holtadit

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Re: Physics Help HERE ONLY !!
« Reply #859 on: January 01, 2010, 09:44:02 am »
Okay I really need help in Paper 3 2008 may Question 5 (c)

Why do you haave to subtract 2.1g from 16.3 grams ?

The Examiners Report says that many student didnt understand the significance of the 2.1g melted in the 2 minutes.

So what is the significance ?

Offline astarmathsandphysics

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Re: Physics Help HERE ONLY !!
« Reply #860 on: January 01, 2010, 10:33:02 am »
The 2.1 g would have melted without the heater

holtadit

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Re: Physics Help HERE ONLY !!
« Reply #861 on: January 01, 2010, 10:40:38 am »
I thought about that too... but the mark scheme says:

using Q=ml  do (2.1-1.3)/4min * 60

If the 2.1 grams melted without the heater in the next 2 minutes why is a total of 4 minutes being used in Q=ml ??


holtadit

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Re: Physics Help HERE ONLY !!
« Reply #862 on: January 01, 2010, 11:31:55 am »
help ?

Offline astarmathsandphysics

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Re: Physics Help HERE ONLY !!
« Reply #863 on: January 01, 2010, 02:09:16 pm »
I will read the q again. I only said what I remembered last time I answered this.

Offline astarmathsandphysics

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