Forces & Elasticity Practice Questions

Which statement describes inelastic distortion?

Put a cross ( ☒ ) in the box next to your answer.

☐ A The object returns to its original shape when the forces are removed.

☐ B The object is permanently changed in shape when the forces are removed.

☐ C The object stores no energy while it is being distorted.

☐ D The object needs only one force acting on it to be distorted.

Explain why more than one force must act on the spring in order to stretch it.

Which statement about a spring is correct?

Put a cross ( ☒ ) in the box next to your answer.

☐ A A spring with a larger spring constant extends more for the same force.

☐ B The spring constant is measured in newtons.

☐ C The extension is directly proportional to the force, up to the limit of proportionality.

☐ D Doubling the force always doubles the extension, however large the force.

The spring in the scale has a spring constant of $200\ \mathrm{N/m}$.

A bag hangs from the scale and pulls on the spring with a force of $6.0\ \mathrm{N}$.

Calculate the extension of the spring.

extension = ............................................... m

Determine the extension of the spring when the weight added is $6.0\ \mathrm{N}$.

extension = ............................................... mm

Calculate the spring constant of this spring.

spring constant = ............................................... N/m

Calculate the force needed to compress the spring by $2.5\ \mathrm{cm}$.

force = ............................................... N

Calculate the energy transferred to the spring's elastic store when it is compressed by $2.5\ \mathrm{cm}$.

Use an equation selected from the list of equations at the end of this paper.

energy transferred = ............................................... J

A chest expander contains a spring of spring constant $450\ \mathrm{N/m}$.

When the spring is fully stretched, $36\ \mathrm{J}$ of energy is transferred to its elastic store.

Calculate the extension of the spring when it is fully stretched.

Use an equation selected from the list of equations at the end of this paper.

extension = ............................................... m

State the extension at which the spring reaches its limit of proportionality.

extension = ............................................... m

Use the area under the graph to estimate the work done in stretching the spring from zero to its limit of proportionality.

work done = ............................................... J

Describe the relationship between force and extension beyond the limit of proportionality.

A student is given a spring, a clamp and stand, a metre rule and a set of $1\ \mathrm{N}$ weights on a hanger.

The student is asked to investigate how the extension of the spring depends on the force applied to it, and to determine the work done in stretching the spring.

Devise a method the student could use.

Your answer should include how the measurements are taken and how the results are used to find the work done.

Give one piece of evidence from the table that shows the extension during loading is not directly proportional to the force.

Explain what the unloading results show about the rubber band.

A spring stretched within its limit of proportionality would give a different set of results.

State one difference.

Calculate the energy transferred to the spring's elastic store when it is stretched from zero to an extension of $4.0\ \mathrm{cm}$.

Use an equation selected from the list of equations at the end of this paper.

energy transferred = ............................................... J

Show that the extra work done in stretching this spring from an extension of $4.0\ \mathrm{cm}$ to an extension of $8.0\ \mathrm{cm}$ is about $0.84\ \mathrm{J}$.

The spring in a door closer is stretched by a force. When the force reaches $40\ \mathrm{N}$, the energy transferred to the elastic store of the spring is $1.2\ \mathrm{J}$.

The spring obeys $F = k \times x$ throughout.

Calculate the spring constant of this spring.

You may use an equation selected from the list of equations at the end of this paper.

spring constant = ............................................... N/m