A position vector of a point is (2i+2j)m a)find magnitude of this vector b) find angle with x-axis c) find - Physics - Motion In A Plane

Question

A position vector of a point is (2i+2j)m
a)find magnitude of this vector
b) find angle with x-axis
c) find the volume of cone which is generated when a line
segment representing this position vector is rotated about x-axis
with one end remaining fixed at origin
ans soon i've test tmrw This chapter is difficult for me to
understand :(

Jyoti Pant · Accepted Answer

Solution: Here position vector =2i+2j (where i and j are unit vectors) a) Magnitude of this vector $\sqrt{2^{2} + 2^{2}} = \sqrt{8} = 2 \sqrt{2}$ b)For the angle with x axis, $\tan θ = \frac{c o e f f i c i e n t o f j}{c o e f f i c i e n t o f i} = 2 / 2 = 1 θ = 45^{0} c) N o w t h e r a d i u s o f c o n e f o r m e d b y t h e p o s i t i o n v e c t o r = 2 u n i t a n d h e i g h t = 2 u n i t S o v o l u m e o f c o n e = \frac{1}{3} π r^{2} h = \frac{1}{3} \times \frac{22}{7} \times 2^{2} \times 2 = 8 38 c u b i c u n i t$