Problem 7.49

กำหนดให้ \(m = 10.0 kg, y = 19.6 m\) และ \(F = 56.6 N\)

จาก \(Σ\vec{F} = m\vec{a}\)

îĵ

\(F - mg = m\vec{a}\)

îĵîĵ

\(\vec{a} =\frac{F}{m}- g = 5.66 - 9.80 m/s^{2}\)

จาก\(\vec{s}=\vec{u}t+\frac{1}{2}\vec{a}t^{2}\)

îĵîĵ

\(x-y=(0)t+\frac{1}{2}(5.66-9.80)t^{2}\)

îĵîĵ

\(x - y = 2.83t^{2} - 4.90t^{2}\)

\(\therefore -y = - 4.90t^{2}\)

\(t^{2} =\frac{y}{4.90}= 4.00 s^{2}\)

และ \(x = 2.83t^{2} = 2.83(4.00)^{2} = 11.32 m\)

จาก \(r = \sqrt{x^{2} + y^{2}}\)

\(r =\sqrt{(11.32 m)^{2} + (19.6 m)^{2}}\)

\(r = 22.6 m \;\blacksquare\)