Table 2 gives test data for three metals considered by a workshop that makes folding ramps for wheelchairs. Each ramp must be easy to carry, but it must als...
Question 1 Report
Table 2 gives test data for three metals considered by a workshop that makes folding ramps for wheelchairs. Each ramp must be easy to carry, but it must also resist bending when a load is placed at its centre. A technician cuts blocks of equal volume from aluminium, steel and copper. The mass is measured on a balance. Each metal strip is then supported at both ends and loaded with a 100 N weight, as shown in Fig. 2.
| Metal | Mass of a 20 cm3 block / g | Downward bend with 100 N load / mm |
|---|---|---|
| aluminium | 54 | 8.0 |
| steel | 156 | 2.0 |
| copper | 178 | 5.5 |
(a) Complete the sentence using a word from the box.
density ductility conductivity
The mass of a given volume of a substance is its ................ . [1]
(b) Use the data for aluminium to calculate its density in g/cm3. [2]
(c) Describe which metal has the greatest resistance to bending. Use Table 2 in your answer. [2]
(d) Suggest the most suitable metal for a ramp where low mass is more important than resistance to bending. Give a reason. [2]
(e) Give two reasons why atoms in a metal allow it to be shaped into a ramp without breaking easily. [2]
Answer Details
(a) The mass of a given volume of a substance is its density. [1]
(b) Use \(\text{density}=\frac{\text{mass}}{\text{volume}}\):
\[\text{density}=\frac{54\text{ g}}{20\text{ cm}^3}=\mathbf{2.7\text{ g/cm}^3}\] [2]
(c) Steel has the greatest resistance to bending. Under the same 100 N load, it bends by only 2.0 mm, less than aluminium at 8.0 mm and copper at 5.5 mm. [2]
(d) Aluminium is most suitable where low mass is more important. Its 20 cm3 block has the lowest mass, 54 g, so it has the lowest density. [2]
(e) Metals contain layers of atoms that can slide past one another. Metallic bonding remains between the atoms/layers, so the metal can change shape without breaking easily. [2]
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