State with reasons, whether the following algebraic operations with scalar and vector physical quantities are meaningful :
$(a)$ adding any two scalars,
$(b)$ adding a scalar to a vector of the same dimensions ,
$(c)$ multiplying any vector by any scalar,
$(d)$ multiplying any two scalars,
$(e)$ adding any two vectors,
$(f)$ adding a component of a vector to the same vector.
$(a)$ Meaningful : The addition of two scalar quantities is meaningful only if they both represent the same physical quantity.
$(b)$ Not Meaningful : The addition of a vector quantity with a scalar quantity is not meaningful.
$(c)$ Meaningful : A scalar can be multiplied with a vector. For example, force is multiplied with time to give impulse.
$(d)$ Meaningful : A scalar, irrespective of the physical quantity it represents, can be multiplied with another scalar having the same or different dimensions.
$(e)$ Meaningful : The addition of two vector quantities is meaningful only if they both represent the same physical quantity.
$(f)$ Meaningful : A component of a vector can be added to the same vector as they both have the same dimensions.
Angular momentum is
A plane covers $500 \,m$ in direction $60^o$ with run-way while starting the flight. Find the distance covered by plane in horizontal and vertical direction.
$100$ coplanar forces each equal to $10 \,N$ act on a body. Each force makes angle $\pi /50$ with the preceding force. What is the resultant of the forces.......... $N$
Define scalar and vector physical quantities with their examples.
If a vector $\overrightarrow P $ making angles $\alpha, \beta\ and\ \gamma$ respectively with the $X, Y$ and $Z$ axes respectively. Then ${\sin ^2}\alpha + {\sin ^2}\beta + {\sin ^2}\gamma = $