Question

A vector 3i+4j is rotated by an angle of 143 degree in clockwise direction,then it becomes ai+bi.Find a and b.

Answer 1

Explanation:

Given a vector as:

a=3i+4j

=>|a|=5

angle between a and x-axis = 53⁰

after rotating about 37⁰ in anticlockwise direction,

new vector = 5j (it will direct toward y axis since 53+37 = 90⁰)

Cheers!!

Regards,

Vikas (B. Tech. 4th year

Thapar University)

Answer 2

Explanation:

The vector is 3i + 4j so to rotate the vector first we need to find the angle θ with which it is making with the x axis.

So, tanθ = y/x which will be tanθ=4/3 = 53 degree.

Thus, the vector is making 53 degree with the x axis hence according to the question if we rotate the vector with 37 degree anticlockwise then the vector will lie entirely in the y axis.

So, the vector will be √(3^2 + 4^2) jcap which will be 5 jcap.