$A$ body of mass $(5 \pm 0.5) \ kg$ is moving with a velocity of $(20 \pm 0.4) \ m/s$. Its kinetic energy will be

In an experiment,the following observations were recorded: $L = 2.820 \, m, M = 3.00 \, kg, l = 0.087 \, cm$,Diameter $D = 0.041 \, cm$. Taking $g = 9.81 \, m/s^2$ and using the formula $Y = \frac{4MgL}{\pi D^2 l}$,the maximum permissible error in $Y$ is ......... $\%$.

$A$ projectile is thrown with velocity $U = 20 \ m/s \pm 5\%$ at an angle $60^{\circ}.$ If the projectile falls back on the ground at the same level,then which of the following values in $m$ cannot be a possible answer for the range?

The time period of a simple harmonic oscillator is $T = 2 \pi \sqrt{\frac{m}{k}}$. The measured value of mass $(m)$ of the object is $10 \ g$ with an accuracy of $10 \ mg$, and the time for $50$ oscillations of the spring is found to be $60 \ s$ using a watch of $2 \ s$ resolution. The percentage error in the determination of the spring constant $(k)$ is . . . . . . %.

$A$ physical quantity $y$ is represented by the formula $y = m^{2} r^{-4} g^{x} l^{-\frac{3}{2}}$. If the percentage errors in $y, m, r, l,$ and $g$ are $18, 1, 0.5, 4,$ and $p$ respectively,then find the value of $x$ and $p$.

Explain the error of a sum or a difference.