OCR A-Level Product Design mathematical and technical principles overview quiz quiz

Force multiplied by the cross-sectional area of the component

Extension divided by the original length of the component

Force divided by cross-sectional area

Stress divided by strain, giving Young's modulus for the material

1.6 MPa

4.0 MPa

400 MPa

40 MPa

No units (it is a ratio)

Pascals, the same unit that is used for stress

Newtons, because strain measures an internal force

Metres, because strain is a measure of length

Strength (the maximum load the material can survive before it fractures)

Stiffness (resistance to elastic deformation)

Density (the mass packed into each unit of the material's volume)

Hardness (the resistance of the surface to scratching and indentation)

26 percent

44 percent

74 percent

12 percent

5.40 pounds

9.60 pounds

15.00 pounds

14.40 pounds

Pi times the radius squared (the radius is half the diameter)

The diameter squared, with no need to involve pi anywhere in the calculation

The diameter multiplied by pi, which actually gives the circumference of the circle

Two times the radius, which is simply another way of writing the diameter

7.6 mm

190 mm

38 mm

43 mm

375 g and 375 g

500 g and 250 g

450 g and 300 g

600 g and 150 g

0.2 mm

40 mm

39.8 mm

0.4 mm

1840 W

28.75 W

238 W

184 W

Velocity ratio divided by mechanical advantage, times 100

Mechanical advantage divided by velocity ratio, times 100

Load times effort

Force times distance

60 percent

120 percent

83 percent

33 percent

Because the load being lifted is always far too heavy for the effort applied

Because the velocity ratio of the machine has been designed or set up incorrectly

Because mechanical advantage is a theoretical idea that cannot actually be measured

Because energy is lost to friction and to moving the machine's own parts