Edexcel Physics: Light Gates query

hey guys
I was just wondering, in the exams, we have to know how to recall certain experiments in order to measure certain values.
If we are asked to recall how to measure velociy for example, how would we explain the setup of the apparatus.

So far my explanation is

-set up a sloping runway and masure it's length
-attach a card of measured length to a trolley and release the trolley
-ensuring it passes through a light gate, use an intelligent timer to time how long it takes to pass through the light gate
-use velocity = displacement/time to calculate velocity

Is this a sufficient explanation. My main query is regarding the 3rd point of my explanation: does it make sense, and how can i improve it?

Would i have to say, connect it to a logit, and the logit to a copmuter to calculate velocity or something similar.

Reply 1

thefish_uk

14

yoko_ono

hey guys
I was just wondering, in the exams, we have to know how to recall certain experiments in order to measure certain values.
If we are asked to recall how to measure velociy for example, how would we explain the setup of the apparatus.

So far my explanation is

-set up a sloping runway and masure it's length
-attach a card of measured length to a trolley and release the trolley
-ensuring it passes through a light gate, use an intelligent timer to time how long it takes to pass through the light gate
-use velocity = displacement/time to calculate velocity

Is this a sufficient explanation. My main query is regarding the 3rd point of my explanation: does it make sense, and how can i improve it?

Would i have to say, connect it to a logit, and the logit to a copmuter to calculate velocity or something similar.

Look in the mark scheme for a paper where a similar question has been asked... personally for GCSE/A-level exams I would give as many points as possible as you don't know which are going to be hoops you have to jump through. It's likely the mark scheme for something like that would have about 6 points but "any 4 will do" or something.

Reply 2

.A.

1. Attach a card of given width W.
2. Use a light gate, at the bottom of the trolley.
3. Electronic timer measures time T for how long it takes the card to pass through the beam.

4. Velocity = displacement/time= w(width of card)/ T

For measuring acceleration, use two light gates. One placed at the top of the trolley and another at the bottom.

The top electronic timer will give you the interpreted time T1 (as I described for the velocity method) . The bottom one will give you T2.

Card width =W. Find U. U = w/T1. Find V. V=w/T2.

Use stop watch to measure T3. This is time between interruptions.

Use U = V + at.

U-V = a(T3) (U-V)/T3 = acceleration.

.A.

Reply 3

yoko_ono

OP

.A.

1. Attach a card of given width W.
2. Use a light gate, at the bottom of the trolley.
3. Electronic timer measures time T for how long it takes the card to pass through the beam.
4. Velocity = displacement/time= w(width of card)/ T

so would this be enough to get full marks, e.g. 4 marks
i looked at the mark schees for similar questions and they give the bear minimum so it is hard to determine what you should write yourself.

Reply 4

Mokuton

..

(edited 12 years ago)

Reply 5

Mokuton

..

(edited 12 years ago)

Reply 6

madushika madugo

Original post by yoko_ono

hey guys
I was just wondering, in the exams, we have to know how to recall certain experiments in order to measure certain values.
If we are asked to recall how to measure velociy for example, how would we explain the setup of the apparatus.

So far my explanation is

-set up a sloping runway and masure it's length
-attach a card of measured length to a trolley and release the trolley
-ensuring it passes through a light gate, use an intelligent timer to time how long it takes to pass through the light gate
use velocity = displacement/time to calculate velocity

Is this a sufficient explanation. My main query is regarding the 3rd point of my explanation: does it make sense, and how can i improve it?

Would i have to say, connect it to a logit, and the logit to a copmuter to calculate velocity or something similar.

there is no need to measure the length of the inclined plane..u hav to measure the length of the card attached to the trolley. and for the third point u cud mention the fact dat data loggers that are connected to the light gate will measure the time taken for the trolley to pass through :smile:

Edexcel Physics: Light Gates query

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