Answer
$μ_k =0.54$
Work Step by Step
We can find acceleration from the slope:
$a = \frac{v_2-v_1}{t_2-t_1}$
$a = \frac{5{m/s} - 0.5{m/s}}{1s-0s}$
$a = 4.5m/s^2$
Finding the coefficient of friction:
$F_{net} = F - f_k$
$ma = F - μ_kF_N$
$μ_k =\frac{F-ma}{F_N}$
$μ_k =\frac{F-ma}{mg}$
$μ_k =\frac{40N-(4.1kg \times 4.5m/s^2)}{4.1kg \times9.8m/s^2}$
$μ_k =0.54$
