If a unit vector is represented by $\vec{U} = 0.9\,\hat{i} - 0.2\,\hat{j} + m\hat{k}$, then the value of m is

The maximum error in the measurement of the density and mass of the uniform cube are 8% and 2% respectively. Hence, the maximum error in the measurement of length will be

For a projectile motion, the range R is 'n' times the maximum height H. So the angle of projection is

An inextensible string passing over a smooth pulley connects two blocks of masses $m_1$ and $m_2$ ($m_2 > m_1$) vertically. If the acceleration of the system is $\left(\dfrac{g}{n}\right)$, then the ratio of masses $\left(\dfrac{m_2}{m_1}\right)$ is