88. We assume the direction of motion is +x and assume the refrigerator starts from rest G the process). The (so that the speed being discussed is the velocity v which results from G only force along the x axis is the x component of the applied force F . (a) Since v0 = 0, the combination of Eq. 2-11 and Eq. 5-2 leads simply to
Fx = m
FG v IJ HtK
vi =
FG F cosθ IJ t H m K i
for i = 1 or 2 (where we denote θ1 = 0 and θ2 = θ for the two cases). Hence, we see that the ratio v2 over v1 is equal to cos θ. (b) Since v0 = 0, the combination of Eq. 2-16 and Eq. 5-2 leads to
F v IJ =mG H 2 Δx K 2
Fx
vi =
2
FG F cosθ IJ Δx H m K i
for i = 1 or 2 (again, θ1 = 0 and θ2 = θ is used for the two cases). In this scenario, we see that the ratio v2 over v1 is equal to cosθ .
