Problem 7.72

î

จาก \(\vec{a}_{t}= 0.50 m/s^{2}\)

ĵĵĵ

จาก \(\vec{a}_{c}= -\frac{v^{2}}{r}= -\frac{(21)^{2}}{500}= -0.88 m/s^{2}\)

\(\therefore |\vec{a}| =\sqrt{(0.50)^{2} + (-0.88)^{2}}= 1.0 m/s^{2} \;\blacksquare\)

จาก \(tanθ = \frac{-0.88}{0.50}\)

\(\theta = \tan ^{-1}(\frac{-0.88}{0.50}) = -60°\)

\(\therefore |\theta | = 60° \;\blacksquare\)