In their first experiment with the apparatus, the students use the double incline to measure the unknown mass of block b. they do this by fixing the value of the right incline at θ=20.0° and then adjusting the value of ϕ for the left incline such that both blocks remain at rest. they find the left incline must be tilted such that ϕ=43.0° . (you can do this experiment for yourself with the simulation! ) what is the mass of block b, mb ?