State what is meant by the centre of mass of a body.
A gymnast performs a high jump over a horizontal bar set at a height of 2.1 m2.1\text{ m}2.1 m above the ground. The maximum increase in gravitational potential energy (g.p.e.\text{g.p.e.}g.p.e.) of the gymnast during the jump is calculated using the expression:
Δg.p.e.=mgh \Delta \text{g.p.e.} = mgh Δg.p.e.=mghExplain why the value of hhh representing the vertical rise of the gymnast's centre of mass is significantly less than 2.1 m2.1\text{ m}2.1 m.
A gymnast performs a vault, starting from rest, running up, launching off a flexible springboard, clearing a vaulting table, and landing stationary on a safety mat.
Describe the energy changes that take place during this entire process, from the initial stationary position before the run-up to the final stationary position after landing on the mat.
533 exam-style questions on CIE IGCSE Physics 1.7 Energy, work and power, covering 1.7.1a Energy stores and energy transfers, 1.7.1b Conservation of energy, 1.7.1c Kinetic and gravitational potential energy, 1.7.2 Work done, 1.7.3 Energy resources, 1.7.3a Energy resources and electricity generation, 1.7.3b Nuclear fusion as an energy source, 1.7.3c Efficiency of energy transfer, and 1.7.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.