General Physics 3 Mock Exam 4

Which of the following factors will generally cause a decrease in the surface tension of a liquid?

A rectangular box of sides $8 \text{ cm}$ by $6 \text{ cm}$ and width $4 \text{ cm}$ is placed on a water surface. Calculate the force due to surface tension on the box if its largest side just touches the water. The surface tension of water is $7 \times 10^{-2} \text{ N m}^{-1}$.

A healthy person has an oral temperature of $98.6^\circ \text{F}$. What would this reading be on the Celsius scale?

A cylindrical steel rod of length $5 \, \text{m}$ and diameter $2 \, \text{cm}$ is stretched by a load of $100 \, \text{kg}$. Calculate the Young's Modulus of the steel if the rod extends by $0.5 \, \text{mm}$. (Assume $g = 9.8 \, \text{m/s}^2$).

A capillary tube with a diameter of $0.4 \text{ mm}$ is vertically placed inside a liquid of density $800 \text{ kg m}^{-3}$. The surface tension of the liquid is $5 \times 10^{-2} \text{ N m}^{-1}$, and the contact angle is $30^\circ$. Calculate the height to which the liquid rises in the capillary tube. Assume $g = 9.8 \text{ m s}^{-2}$.

A patient's body temperature is recorded as $102.2^{\circ}F$. What is this temperature when expressed on the Celsius scale? Use the conversion formula $T_C = \frac{5}{9}(T_F - 32)$.

The flow rate of a liquid through a pipe is found to be $Q$. If the radius of the pipe is doubled while keeping the pressure difference, length, and viscosity constant, what will be the new flow rate?

A container of water is heated, causing its temperature to rise from $15^{\circ}C$ to $65^{\circ}C$. Calculate the change in temperature on the Fahrenheit scale. Use the relationship $\Delta T_F = \frac{9}{5}\Delta T_C$.

A soap bubble has a diameter of $2 \, \text{mm}$. If the surface tension of the soap solution is $2.8 \times 10^{-2} \, \text{N/m}$, what is the excess pressure inside the bubble compared to the outside atmospheric pressure?

Consider a sealed container filled with a gas. If one side of the container is heated, the gas molecules near that side gain kinetic energy and move faster. However, if the container is perfectly rigid and the gas volume is constant, what happens to the overall heat transfer by convection within the gas?