Question

A taut massless string connects two boxes as shown in the figure. The boxes are placed on an incline plane at θ = 31.00. What is the acceleration of boxes as they move down the incline, given m2 = 1.6 kg, m1 = 7.6 kg, μ2 = 0.10 and μ1 = 0.20.

Please help! I have no idea how to do this. I can sum my forces but i just get an extremely high acceleration.

Answer 1

I will assume ox 1 is uphill so it drags back on box 2 and they accelerate together

Forces down slope
(7.6 +1.6) g sin 31 = 4.74 g

Forces up slope
(7.6*.2 +1.6*.1) g cos 31 = 1.44 g

total mass = 7.6+1.6 = 9.2 kg

so
(4.74-1.44)g = 9.2 a
a = .359 g
if g = 9.81 m/s^2
a = 3.52 m/s^2

Answer 2

Okay, this helped a little! Thank you for answering. This may be a dumb question but where did you get 4.74 and 1.44?