Materials

A spring extends by 12 cm when a mass of 87 g is attached to it. Calculate the spring constant. g = 9.81 ms^-2

If the deformation of the material is plastic, the material __________.

Under a 4 N force, two identical springs, in parallel, stretch 130 mm. Calculate the spring constant for one of the springs.

Estimate k from the graph shown above.

A meteor traveling through space has a k = 4.2x10⁶ Nm^-1 and a force of 5x10⁸ N. Calculate the extension of the meteor.

Two nichrome wires, A and B, have a load of 30 N placed on them each. The original lengths of the wires are 3 m and 2 m. Each wire shows the same extension. Find the ratio of A_k to B_k.

At which point on the graph shown above is the elastic limit?

What is another term for tensile deformation?

This graph shows the extension of 4 different springs, which spring is the stiffest?

What is the relationship between the force applied, F, and the extension, x of a material that obeys Hooke's Law?

Two springs attached in series extend by 5 cm when a load of F is applied to them. They have different constants of 76 Nm^-1 and 31 Nm^-1 respectively. Calculate the value of F.

When plotting a force extension graph for the loading and unloading of a material, when would the unloading line not pass through the origin?

A wire has a diameter of 0.5 mm and a breaking stress of the wire is 7.4x10¹⁰ Nm^-2. Calculate the mass that would break the wire. g = 9.81 ms^-2

A wire of 1.2 m extends a 3 mm when a load of 20 N is applied to it. Calculate it's strain.

A stress-strain graph is shown above for an unknown material. Where on the curve would you mark the UTS point?

The graph above shows a fishing wire being extended by adding masses. Use the graph to estimate the elastic strain energy of the material.

A copper wire has a length of 25 cm and a force of 400 N is applied to the wire, which causes it to stretch to 28.9 cm. Calculate the elastic strain energy stored in the wire.

A wire has a diameter of d and a when a force of F is applied, it breaks at σ. What would the value of σ be if the diameter was halved?

A new material is developed and the research team want to know the amount of elastic strain energy it can store. They test the material multiple times and plot a graph with the averages. Estimate from the graph the elastic strain energy that is stored in the wire up to the limit of proportionality.

Select the graph with the correct labels.

Which material on the graph above is the weakest?

Which material on the graph above is the stiffest?

Which material on the graph above is the strongest?

A 500 mm material undergoes a strain of -3.2%, when measured what is the materials length?

A material has a stress of 6x10⁸ Nm^-2 and is placed under a 5% strain. Calculate the value for the materials Young's modulus.

What is Young's modulus a measure of?

What is the units for Young's modulus in terms of SI units?

The graph above shows a wire being extended by adding masses. Estimate from the graph the Young's modulus.

When investigating Young's modulus, why should you use a long wire?

The Young's Modulus for a single walled carbon fibre nanotubes of diameter 4 nm is 1000 GPa. If it is placed under 75% strain, what force is required to break it?

Stress and strain are used to calculate the Young's modulus of a material up to its _____________.

A unknown material under load 75 N incurs an extension of 2.1 mm. The original length of the material was 1.75 m and it has a diameter of 0.45 mm. Which material is it most likely to be?

A copper wire of diameter 0.6 mm, X, is joined in series to the end of another copper wire of diameter 0.125 mm, Y. Both wires are 80 cm in length when no load is applied. A 15 N load is hung on the end of the wires as shown in the diagram below. If the Young's Modulus of copper is 128 GPa, calculate the extension for each wire.

Two wires, Q and W, are connected in series and a force, F is applied. Q and W have the same length, l the same diameter, d but are made from different materials. Therefore, the Young's Modulus of Q, E, is twice the value of W. Which expression is correct for the total extension in the system?

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?