A level maths
A rope is passed over a smooth beam. Two children, the heavier of which has mass 60 kg, hang on to the rope, one on either end, so that the heavier one descends with an acceleration of 2 ms-2. The mass of the lighter child, to the nearest kilogram, is.....kg
Reply 1
Original post
by ForesterrrA rope is passed over a smooth beam. Two children, the heavier of which has mass 60 kg, hang on to the rope, one on either end, so that the heavier one descends with an acceleration of 2 ms-2. The mass of the lighter child, to the nearest kilogram, is.....kg
It would be great that you explain what is the problem that you are facing in doing this problem.
It is always good to draw a simple diagram (aka free-body diagram) to show all the forces acting on the heavier child.
Recall N2L as Fnet = ma.
Can you continue from here?
Reply 2
Original post
by ForesterrrA rope is passed over a smooth beam. Two children, the heavier of which has mass 60 kg, hang on to the rope, one on either end, so that the heavier one descends with an acceleration of 2 ms-2. The mass of the lighter child, to the nearest kilogram, is.....kg
It is best to do it yourself.
Here's a tip:
Okay, so for the heavier kid: There is gravity pulling them downwards. To find that force, use their mass (m1 = 60 kg) and acceleration due to gravity (g = 9.8 ms^-2). The rope's also pulling up on them. We refer to that force as tension. Let's refer to how strong it is.
Now, for the lighter child: The same thing, gravity's attracting them downward. Let's set their mass to m2.
Once more, the rope is subjected to an upward force due to tension (T). If the rope is ideal and the beam is smooth, what can be said about the tension and tension experienced by the heavier child?
Use Newton's Second Law (F=mg) for both cases. For each child, consider the forces pulling them downwards and the forces pulling them upwards (give opposite signs for acceleration).
Find the tension (T) and mass of a lighter child. Check the consistency of your units. Let me know if you need help!
Here is my 2 cents!
Reply 3
Original post
by Nitrotoluene.....
Use Newton's Second Law (F=mg) for both cases.
...
Use Newton's Second Law (F=mg) for both cases.
...
We don't write Newton's Second Law as F = mg, in fact, mg is the weight NOT net force.
Reply 4
Original post
by EimmanuelWe don't write Newton's Second Law as F = mg, in fact, mg is the weight NOT net force.
Hello, Eimmanuel!
I have checked my suggestions carefully and you are right about Newton's second law.
However, it seems to me that with some more information, such as knowing the speed at which the system is accelerating (a), I think we could solve the problem by understanding the tension (T) and the mass of the lighter child (m2).
What do you think of my comment above?
Bye,
Sandro
Reply 5
Original post
by NitrotolueneHello, Eimmanuel!
I have checked my suggestions carefully and you are right about Newton's second law.
However, it seems to me that with some more information, such as knowing the speed at which the system is accelerating (a), I think we could solve the problem by understanding the tension (T) and the mass of the lighter child (m2).
What do you think of my comment above?
Bye,
Sandro
I have checked my suggestions carefully and you are right about Newton's second law.
However, it seems to me that with some more information, such as knowing the speed at which the system is accelerating (a), I think we could solve the problem by understanding the tension (T) and the mass of the lighter child (m2).
What do you think of my comment above?
Bye,
Sandro
We don't need to know the speed as Fnet is related to acceleration NOT speed.
In fact, we can solve the problem in a "single step".
This is a modified Atwood Machine problem.
We shall let OP respond to the replies first before making additional comments.
Quick Reply
Related discussions
- Which out of Oxford and Cambridge is more likely to make an offer to me with 3 A-leve
- Further Math without Math?
- Should I do Math A-Level?
- Further maths GSCE to A LEVEL maths
- Is further maths actually worth anything ??
- Oxford PPE without maths a levels
- A level options
- Should I apply for a PPE at Oxford?
- Politics, history, philosophy or further maths
- AS and A level maths and science revision websites
- Further Maths
- Is maths a level really that important?
- A Level options for maths degree
- A-Levels HELP
- How hard is A level maths realistically
- PPE at Oxford requirements
- Sat instead of a level maths
- How hard is a level physics
- Maths vs Psychology A Level
- A-level: AQA Physics, or Edexcel Further Maths
Latest
Trending
Last reply 8 months ago
Help with british physics olympiad compuational challenge (BphO)Last reply 9 months ago
Is anyone trying to qualify for the International physics Olympiad
How The Student Room is moderated
To keep The Student Room safe for everyone, we moderate posts that are added to the site.
