Zero error of an instrument introduces

The relative density of the material of a body is found by weighing it first in air and then in water. If the weight in air is $(5.00 \pm 0.05) \ N$ and the weight in water is $(4.00 \pm 0.05) \ N$,then the relative density along with the maximum permissible percentage error is:

The temperatures of two bodies measured by a thermometer are $t_{1} = 20^{\circ}C \pm 0.5^{\circ}C$ and $t_{2} = 50^{\circ}C \pm 0.5^{\circ}C$. Calculate the temperature difference and the error therein.

If $P = \frac{A^3}{B^{5/2}}$ and $\Delta A$ is the absolute error in $A$ and $\Delta B$ is the absolute error in $B$,then the absolute error $\Delta P$ in $P$ is:

Explain the statement: "The accuracy of a measurement cannot be determined by absolute error,but only by percentage error."

The percentage errors in the measurement of mass and speed are $2\%$ and $3\%$ respectively. What will be the maximum percentage error in the estimation of the kinetic energy obtained by measuring mass and speed?