Question

A body starts from rest from the origin with an acceleration of $6m/s^{2}$ along the x-axis and $8m/s^{2}$ along the y-axis. Its distance from the origin after 4 seconds will be

• A. 56 m
• B. 64 m
• C. 80 m
• D. 128 m

Answer 1

Answer: (C)

80 m

Answer 2

$S_{x} = u_{x}t + \frac{1}{2}a_{x}t^{2} \Rightarrow S_{x} = \frac{1}{2} \times 6 \times 16 = 48\mspace{6mu} m$

$S_{y} = u_{y}t + \frac{1}{2}a_{y}t^{2} \Rightarrow S_{y} = \frac{1}{2} \times 8 \times 16 = 64\mspace{6mu} m$

$S = \sqrt{S_{x}^{2} + S_{y}^{2}} = 80m$