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Motion In A Plane

Question
CBSEENPH11020807
Wired Faculty App

The vectors bold A with bold rightwards arrow on top space and space bold B with bold rightwards arrow on top are such that a:
open vertical bar straight A with rightwards arrow on top plus straight B with rightwards arrow on top close vertical bar space equals space open vertical bar straight A with rightwards arrow on top space minus space straight B with rightwards arrow on top close vertical bar
The  angle between the two vectors is

  • 90 degree
  • 60 degree
  • 75 degree
  • 45 degree

Solution

A.

90 degree

As we have given
        open vertical bar straight A with rightwards arrow on top plus straight B with rightwards arrow on top close vertical bar space equals open vertical bar straight A with rightwards arrow on top minus straight B with rightwards arrow on top close vertical bar or space space space square root of straight A squared plus straight B squared plus 2 AB space Cosθ end root space equals square root of straight A squared plus straight B squared minus 2 AB space Cos space straight theta end root
where straight theta is the angle between straight A with rightwards arrow on top space and space straight B with rightwards arrow on top
Squaring both sides, we have
straight A squared plus straight B squared plus 2 AB space Cosθ space equals space straight A squared plus straight B squared minus 2 AB space cosθ or space space space space space space space space space space space space space space space space space space 4 AB space cosθ space equals space 0 As space space space space space space space space space space space space space space space space space AB not equal to 0 therefore space space space space space space space space space space cosθ space equals space 0 space equals space cos space 90 degree therefore space space space space space space space space space space space space space space space space space space space space space space space straight theta space equals space 90 degree space space space space space space space space space space space space
Hence, angle between stack straight A space with rightwards arrow on top and space straight B with rightwards arrow on top space is space 90 degree

Some More Questions From Motion in A Plane Chapter

Which of the followings is/are vector quantities: work, power, acceleration, mass, momentum?

Pick up the odd one from the following: force, linear momentum, mass, impulse.

Pick out the only vector quantities in the following list:
Temperature, pressure, impulse, time, power, total path length, energy, gravitational potential, coefficient of friction and charge.

Pick out the two scalar quantities in the following list:
force, angular momentum, work, current, linear momentum, electric field, average velocity, magnetic moment, reaction as per Newton’s third law, relative velocity.

What are polar vectors?

Give two examples of polar vectors.

What are axial vectors?

Give two examples of axial vectors.

What are tensors?

Give one example of tensor.

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