- #1

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As given by the attached question, we are given:

I think the relevant equations are:

ƩFy = 0;

ƩFx = ma;

F(friction) = N*μ

My attempt of the solution involved choosing my axis to be parallel to the slope (x axis) and y axis perpendicular to the slope, then breaking the 51N force on the pulley up into it's components, i.e;

for x direction: 51cos(31)

for y direction: 51sin(31)

Then break up the boxes weight force into x & y components, i.e.

for x direction: (15*9.81)*cos(31)

for y direction: (15*9.81)*sin(31)

Next I summed the forces in the y direction to find the normal force N

i.e.

Giving

Next I found the force for friction giving:

So then I tried to calculate the forces in the x direction with the positive direction being up the slope

ƩFx = 24.7605 + 51cos(31) + T - (15*9.81)*cos(31) + F = 15 * a

However I do not know where to find T, or if any of this working is correct, I'd really like some guidance on where to go from here, thanks.

- The force on the pulley, 51N
- The angle of the pulley, 31 degrees
- The mass of the box, 15 kg
- The angle of the incline, 31 degrees
- The kinetic friction coefficient, 0.5

I think the relevant equations are:

ƩFy = 0;

ƩFx = ma;

F(friction) = N*μ

My attempt of the solution involved choosing my axis to be parallel to the slope (x axis) and y axis perpendicular to the slope, then breaking the 51N force on the pulley up into it's components, i.e;

for x direction: 51cos(31)

for y direction: 51sin(31)

Then break up the boxes weight force into x & y components, i.e.

for x direction: (15*9.81)*cos(31)

for y direction: (15*9.81)*sin(31)

Next I summed the forces in the y direction to find the normal force N

i.e.

**ƩFy = -(15*9.81*sin(31))+N+51(sin(31) = 0**Giving

**N = 49.521**Next I found the force for friction giving:

**F = 49.521*0.5**

F = 24.7605F = 24.7605

So then I tried to calculate the forces in the x direction with the positive direction being up the slope

ƩFx = 24.7605 + 51cos(31) + T - (15*9.81)*cos(31) + F = 15 * a

However I do not know where to find T, or if any of this working is correct, I'd really like some guidance on where to go from here, thanks.