U4.4 – Density & Forces in Fluids

Which material is the densest?

A 4.2 g balloon is inflated with 1.8 g of air until it is 1.4x10^-3 m³ in volume. Calculate the density of the inflated balloon.

Which diagram is showing laminar flow?

A steel ball bearing is dropped into a fluid and travels 60 cm in 2.53 s. The diameter of the ball bearing is 6 mm and its mass 15.3 g. Calculate the viscosity of the fluid. g=9.81 Nkg^-1

What conditions are required for Stokes's law to apply?

When the temperature increases, what is the effect on fluids' viscosities?

In order to calculate viscous drag (F), the equation above is used. What is a unit for η?

The ship, Queen Elizabeth 2, was a cruise ship from 1969-2008. She currently resides in Mina Rashid, Dubai as a floating hotel. When fully laden she held 70,327 tonnes and therefore displaces that weight of fluid when afloat. If the the density of seawater is 1024 kgm^-3, calculate the upthrust exerted on the ship when she was afloat fully laden. g = 9.81 NKg^-1

When a ball bearing is dropped through a liquid of unknown viscosity, the sum of all the forces equal ___________.

HMS Astute is a nuclear-powered submarine in service with the Royal Navy, she can dive to depth of 300 m in seawater of density 1024 kgm^-3. If the pressure inside the submarine is kept at sea level (1.01x10⁵ Pa), calculate the resultant force on a section of the hull of area 20 m² at her maximum depth.

A ball bearing of diameter 5.6 mm is dropped into a liquid which has a viscosity of 5.4 Pa s and a density of 1.38 kgL^-1. In the liquid, it reaches a terminal velocity of 0.023 ms^-1. Calculate the mass of the ball bearing. g=9.81 Nkg^-1

When undertaking practical work to measure the viscosity of liquid, why should the marker the signifies timer start be approximately halfway down the tube?