A cargo barge is constructed from steel. The density of steel is 7850 kg/m37850\text{ kg/m}^37850 kg/m3 and the density of seawater is 1025 kg/m31025\text{ kg/m}^31025 kg/m3.
Explain why the steel barge is able to float in seawater.
When loading the barge, the heaviest cargo is placed as low as possible at the bottom of the hull.
State and explain the effect of loading the heavy cargo in this way on the stability of the barge.
A dockside crane lifts a heavy piece of machinery of mass 24 000 kg24\,000\text{ kg}24000 kg vertically upwards through a distance of 35 m35\text{ m}35 m.
Calculate the energy transferred to the gravitational potential energy store of the machinery. (Take the acceleration due to gravity, g=9.8 m/s2g = 9.8\text{ m/s}^2g=9.8 m/s2)
245 exam-style questions on CIE IGCSE Physics 1.5 Forces, covering 1.5.1a Forces, resultant force and motion, 1.5.1b Load–extension graphs and the spring constant, 1.5.1c Friction and drag, 1.5.1d Force, mass and acceleration, 1.5.1e Motion in a circular path, 1.5.2a Moment of a force, 1.5.2b Principle of moments and equilibrium, and 1.5.3 Centre of gravity and stability. Each one has a worked solution and a mark scheme showing where the marks go.