Turn on thread page Beta
    • Thread Starter

    Name:  18493878_755662441303070_161214932_o.jpg
Views: 86
Size:  66.1 KBHelp pls, thank you

    To help you understand these questions, I suggest redrawing the diagram with arrows labelling all of the forces and their magnitudes and directions, and which direction the acceleration is in. I have done one for you to help get you started

    For 3i), you can now make equations for each block by resolving the forces.
    For the block weighing 8kg, which we'll call Block A, the motion is horizontal therefore we have to resolve the horizontal forces to get this equation:
    T - F = 8a. Remember that F = ma (the resultant force is the mass multiplied by the acceleration), and the block is moving in the same direction as the tension.
    But since the table is said to be smooth, there is no friction, so F = 0, and the tension would therefore be 8a.

    We can also resolve vertically for the block that weighs 4kg, Block B:
    4g - T = 4a. Since the direction motion is downwards, the tension would be negative in this case. g = 9.8.
    Now that you have your equations, you can sub in the value of T you found earlier into the equation for Block B to find the acceleration for 3ii.

    For 3iii, draw another diagram showing the direction of the forces, and resolve in directions perpendicular and parallel to the plane for each of the two boxes.

    Now, when the system is in equilibrium, there is no movement, therefore the equations you form when you resolve should be equal to 0, allowing you to find unknown values.
    I'll get you started on one equation as an example:
    For block weighing 8kg, R(perpendicular to plane) = R - 8gcosϴ = 0.
    R = 8gcosϴ

    After you've done the other equations, try and make simultaneous equations with the expressions you found to try and find ϴ.

    I'm not very good at explaining things, but I hope this is of any help to you. ^-^
    (please ignore the duplicate of the diagram below - I've no idea why that's appearing)
    Attached Images
Submit reply
Turn on thread page Beta
Updated: May 14, 2017

University open days

  • Sheffield Hallam University
    City Campus Postgraduate
    Wed, 17 Oct '18
  • Northumbria University
    All faculties Undergraduate
    Wed, 17 Oct '18
  • Staffordshire University
    Nursing and Midwifery Undergraduate
    Wed, 17 Oct '18
Who is most responsible for your success at university
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here


How to use LaTex

Writing equations the easy way


Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.