Grade 12 Physics S1M2

A student experimented on a metal wire; the graph below was plotted.

The area under the graph shows the toral strain energy stored in the wire when stretched. How should the axes be labelled?

• Y- mass

  X- extension

• Y- force

  X- extension

• Y- strain

  X- energy

• Y- stress

  X- strain

1A student drew a force-extension graph for a sample of metals. She subjected the sample to a force that increased to a maximum and then decreased to zero. When the sample contracts it follows the same force-extension curve as when it was being stretched. What is the behaviour of the metal between S and T?

• Both elastic and plastic

• Elastic but not plastic

• Not elastic and not plastic

• Plastic but not elastic

A metal wire had a tension F and extension x with a Young modulus of E; the wire obeyed Hooke’s law.

Which expression represents the elastic strain energy stored in the wire?

Which of the following is the correct definition of elastic and plastic behaviour?

• A

• B

• C

• D

The graphs below all show force-extension graphs; they are all drawn to the same scale.

Which graph shows the object that has been deformed and has the greatest amount of elastic potential energy?

• A

• B

• C

• D

A spring is extended with varying forces; the graph below shows the results. What is the energy stored in the spring when the extension is 30 mm?

• 0.25 J

• 0.95 J

• 0.095 J

• 0.19 J

A force compresses a mattress spring by 100 mm. The graph shows the effect of force F on the length l of the string. What is the energy stored in the spring when the length is 70 mm?

• 0.63 J

• 0.27 J

• 0.21 J

• 0.090 J

A spring is extended due to a force. The graph shows the effect of changing force on the extension of the spring. What is the elastic potential energy of the spring with a force of 8.0 N?

• 152 mJ

• 58 mJ

• 85 mJ

• 5.8 mJ

The diagram shows four water molecules in a swimming pool. It also shows how much energy each molecule has. Which of the water molecules is most likely to evaporate from the liquid?

• Molecule A

• Molecule B

• Molecule C

• Molecule D

A popular demonstration of kinetic theory is to view smoke particles through a microscope while illuminating them with a bright light.        

The diagram shows the view of the smoke particles through a microscope. They are moving about randomly. What causes the motion of the smoke particles?

• The smoke particles are attracted to each other.

• The smoke particles vibrate because they are warm.

• Smaller air particles are colliding with the smoke particles.

• the microscope is vibrating slightly, making the smoke particles appear to move.