Physics Edexcel Specimen question

In summary: If you double the area of the umbrella you will double the amount of water making contact with it. Also, if we are asking how much rain will hit in a certain amount of time and if we assume the density of raindrops to be constant, then we will need to know the velocity of the rainfall. You might be able to see that the amount of water hitting the umbrella in a certain amount of time is contained in a cylindrical column of water with an end area equal to the umbrella’s area and the height given by the velocity of rainfall times the time we are concerned with.
  • #1
jsmith613
614
0

Homework Statement



http://www.edexcel.com/migrationdocuments/GCE New GCE/sam-gce-physics.pdf

Unit 4 Q18)
"A do-it-yourself..."
could someone please explain to me ci) and cii)

Homework Equations



I cannot think of any equation to help me

The Attempt at a Solution


I looked at the mark-scheme and they said mass = Area * velocity
What I don't understand is why this is true

for cii)
Force = mass * acceleration
so acceleration (moving in a circle) = v^2/r
acceleration = (14*14)/0.9 = 217.78
But this would give an enourmous answer to cii) which is far greater than the correct answer?
 
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  • #2
Regarding section (c)(i),
I will try to help by offering an analogy; imagine someone standing in the rain with an umbrella, the rain falls straight down and the umbrella is held conventionally with the protective surface horizontal. If you were to ask how much rain is hitting the umbrella it should be easy to see that the area of the umbrella is directly related to the amount of water that will hit. If you double the area of the umbrella you will double the amount of water making contact with it. Also, if we are asking how much rain will hit in a certain amount of time and if we assume the density of raindrops to be constant, then we will need to know the velocity of the rainfall. You might be able to see that the amount of water hitting the umbrella in a certain amount of time is contained in a cylindrical column of water with an end area equal to the umbrella’s area and the height given by the velocity of rainfall times the time we are concerned with.
To relate this to your problem, you are given the area swept out by the blades and the velocity of the wind. The density of air is constant and the problem is concerned with a 1 second time period.
“...the mark-scheme and they said mass = Area * velocity...”
Technically speaking this is incorrect.
The correct statement is mass=density*volume=density*area* length=density*area*velocity* time
The “mark scheme” left out density and time. In this case, since the time is 1 sec, the numerical value of time can be “left out” since it is 1, leaving density*area*velocity.
I hope this makes sense and is helpful.
 
  • #3
Yes I much prefer you answer.
but for cii) I still get too big an answer. Have I calculated acceleration incorrectly.
 
  • #4
please could someone help me with the second part of the question. THanks
 
  • #5
I believe it has something to do with momentum but not sure what
 

1. What is the format and structure of the Physics Edexcel Specimen question?

The Physics Edexcel Specimen question is divided into two papers: Paper 1 and Paper 2. Each paper is further divided into two sections: Section A and Section B. Section A consists of multiple choice questions, while Section B contains longer answer questions. The total marks for each paper is 100, with Paper 1 being 35% of the overall grade and Paper 2 being 65%.

2. How many questions are there in the Physics Edexcel Specimen question?

There are a total of 60 questions in the Physics Edexcel Specimen question, with 30 questions in Paper 1 and 30 questions in Paper 2. Each question is worth 2 marks, except for the longer answer questions in Paper 2 which are worth 5-8 marks.

3. What topics are covered in the Physics Edexcel Specimen question?

The Physics Edexcel Specimen question covers a wide range of topics in physics, including mechanics, electricity, waves, particles and radiation, and energy. It also includes topics such as thermal physics, nuclear physics, and astrophysics.

4. How much time is given to complete the Physics Edexcel Specimen question?

Students are given a total of 2 hours and 15 minutes to complete the Physics Edexcel Specimen question. This includes 1 hour and 30 minutes for Paper 1 and 45 minutes for Paper 2.

5. What resources are allowed during the Physics Edexcel Specimen question?

Students are not allowed to bring any resources or aids into the exam room for the Physics Edexcel Specimen question. This includes calculators, formula sheets, and textbooks. However, a periodic table and data sheet will be provided for use during the exam.

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