A2 Maths (mechanics)

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Reebz.F

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Mar 30, 2020 2:38 am

(@reebz-f)

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Hello ?,

Does anyone know how to do any of these questions?

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#maths

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Further_Maths_Student

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Mar 30, 2020 2:43 am

(@further_maths_student)

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first question you sent which says "show that OA = ..." means you need to find the horizontal distance between O and A. (horizontal motion means s = d/t, rearrange and work out d). speed you need to work out via resolving and time you need to work out by considering the vertical motion

the second question "find the range of possible values for mu (coef of fric)", the particle is moving up. This means that the forces going against the direction of motion is less than the forces going upwards. Make an equation from this information;

forces opposite direction of motion parallel to plane < forces in direction of motion parallel to plane

Then rearrange for mu (coef of fric)

Reebz.F

(@reebz-f)

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Mar 30, 2020 7:55 pm

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Further_Maths_Student

@further_maths_student that's what I've tried doing but the answers that I'm getting are wrong.

Further_Maths_Student

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(@further_maths_student)

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Mar 30, 2020 8:31 pm

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Reebz.F

@reebz-f

Distance (OA) = speed x time, where speed = ucos(theta) and time we need to work out via considering vertical motion. By considering vertical motion I constructed s = ut +1/2 at^2 then solved for t

‘then plugged t into speed = distance x time

As for this question, only force going upwards was the 30n which resolved to 30 cos(theta) and the two forces acting down the plane was the friction and weight which we have to resolve - then simplify and solve the inequality as we know tan(theta)

sorry got messy writing, were those answers correct?