- #1

soysauce

- 2

- 0

## Homework Statement

Hi everyone, I hope you're enjoying your weekends!

I've been trying this question for a while not having any luck, I'm hoping someone can tell me where I'm going wrong

The question is:

Two boxes are connected by a rope that passes through a pulley on the corner of a incline. Box A is 2.5 kg and box B is 5.5 kg. The coefficient of kinetic friction on the incline is 0.54. Box A is on the incline and box B hangs over. The angle of the incline is 25.4º. Find the acceleration and the tension.

The answers given are 3.8 m/s2 [down] and 33 N [up]

## Homework Equations

I got these equations from here:https://www.physicsforums.com/showthread.php?t=27346 and I understand why I would use them

F

_{t}= m

_{1}*a + m

_{1}gcosθ + μm

_{1}gcosθ and

F

_{t}= m

_{2}(g-a)

## The Attempt at a Solution

m1 = 2.5 kg, m2 = 5.5 kg, μ = 0.54, θ = 25.4°

I know I can equate the two tension equations to get:

m

_{2}(g-a) = m

_{1}*a + m

_{1}gcosθ + μm

_{1}gcosθ

But when I plug in the known values and solve:

5.5(9.8-a) = 2.5*a + 2.5*9.8*cos(25.4) + 0.54*2.5*9.8cos(25.4)

I get a value of a = 2.4

Could someone tell me where I'm going wrong here?

Thanks so much in advance!