If $\overrightarrow A = 2\hat i + 4\hat j - 5\hat k$ the direction of cosines of the vector $\overrightarrow A $ are
If $\overrightarrow A = 2\hat i + 4\hat j - 5\hat k$ the direction of cosines of the vector $\overrightarrow A $ are
- A
$\frac{2}{{\sqrt {45} }},\frac{4}{{\sqrt {45} }}\,{\rm{and}}\,\frac{{ - \,{\rm{5}}}}{{\sqrt {{\rm{45}}} }}$
- B
$\frac{1}{{\sqrt {45} }},\frac{2}{{\sqrt {45} }}\,{\rm{and}}\,\frac{{\rm{3}}}{{\sqrt {{\rm{45}}} }}$
- C
$\frac{4}{{\sqrt {45} }},\,0\,{\rm{and}}\,\frac{{\rm{4}}}{{\sqrt {45} }}$
- D
$\frac{3}{{\sqrt {45} }},\frac{2}{{\sqrt {45} }}\,{\rm{and}}\,\frac{{\rm{5}}}{{\sqrt {{\rm{45}}} }}$
Similar Questions
Read each statement below carefully and state with reasons, if it is true or false :
$(a)$ The magnitude of a vector is always a scalar,
$(b)$ each component of a vector is always a scalar,
$(c)$ the total path length is always equal to the magnitude of the displacement vector of a particle.
$(d)$ the average speed of a particle (defined as total path length divided by the time taken to cover the path) is either greater or equal to the magnitude of average velocity of the particle over the same interval of time,
$(e)$ Three vectors not lying in a plane can never add up to give a null vector.
Read each statement below carefully and state with reasons, if it is true or false :
$(a)$ The magnitude of a vector is always a scalar,
$(b)$ each component of a vector is always a scalar,
$(c)$ the total path length is always equal to the magnitude of the displacement vector of a particle.
$(d)$ the average speed of a particle (defined as total path length divided by the time taken to cover the path) is either greater or equal to the magnitude of average velocity of the particle over the same interval of time,
$(e)$ Three vectors not lying in a plane can never add up to give a null vector.
Any vector in an arbitrary direction can always be replaced by two (or three)
Any vector in an arbitrary direction can always be replaced by two (or three)
How the magnitude of vector quantity is represented ?
How the magnitude of vector quantity is represented ?
A force vector applied on a mass is represented as $\vec F = 6\hat i - 8\hat j + 10\hat k$ and accelerates with $1\;m/{s^2}$. What will be the mass of the body in $kg$.
A force vector applied on a mass is represented as $\vec F = 6\hat i - 8\hat j + 10\hat k$ and accelerates with $1\;m/{s^2}$. What will be the mass of the body in $kg$.
Given vector $\overrightarrow A = 2\hat i + 3\hat j, $ the angle between $\overrightarrow A $and $y-$axis is
Given vector $\overrightarrow A = 2\hat i + 3\hat j, $ the angle between $\overrightarrow A $and $y-$axis is