K A Tsokos Solutions for Chapter: Measurement and Uncertainties, Exercise 4: Exam-style questions

In which of the following diagrams do the three forces add up to zero?

Three forces act on a body as shown.

A force of $25 \mathrm{N}$ acts normally on a surface of area $5.0 {\mathrm{cm}}^2$. What is the pressure on the surface in $\mathrm{N} {\mathrm{m}}^{-2}$.

The side of a cube is measured with an uncertainty of $2\%$. What is the uncertainty in the volume of the cube?

The flow rate $Q$ through a tube length $L$ and radius $r$ whose ends are kept at a pressure difference $∆P$ is given by $Q=\frac{c{r}^4∆P}{L}$, where $c$ is constant. The percentage uncertainty of which quantity has the largest effect on the percentage uncertainty in $Q$?

The force of air resistance $F$ on a car depends on speed $v$ through the formula $F=a{v}^2+bv$, where $a$ and $b$ are constants. Which of the following graphs will result in a straight-line graph?

The diagram shows the temperature of a liquid before and after heating.

Which is the best estimate for the temperature increase of the liquid?

A student wishes to measure the acceleration of free fall by letting a ping pong ball drop from one fixed height from the floor. He measures the height. Using a stopwatch, he measures the time for the ball to drop to the floor. He then uses the equation $h=\frac{1}{2}g{t}^2$ to calculate $g$.

State and discuss three improvements to the student's lab experiment.