Halliday, Resnick & Walker — Force and Motion–II: Problem 32_M_GO

A block is pushed across a floor by a constant force that is applied at downward angle \(\theta\) (Fig. 6.8). Figure 6.25 gives the acceleration magnitude \(a\) versus a range of values for the coefficient of kinetic friction \(\mu_k\) between block and floor: \(a_1 = 3.0 \text{ m/s}^2\), \(\mu_{k2} = 0.20\), and \(\mu_{k3} = 0.40\). What is the value of \(\theta\)?