A heavy hinged trapdoor is installed in a wooden floor.
State the physics term for the turning effect of a force.
The trapdoor is to be lifted by a vertical force FFF acting upwards. Explain where on the trapdoor this force should be applied so that its magnitude is as small as possible.
A tall, uniform rectangular wooden block is placed upright on a flat ramp.
The ramp is gradually tilted at one end so that the angle of inclination increases. The block does not slide. State what will eventually happen to the block as the ramp is tilted further.
Explain this behavior in terms of the position of the block's centre of mass and its base of support.
Many mobile workshop tool cabinets on wheels have a safety interlock system that prevents more than one drawer from being opened at a same time. Explain why it is dangerous to open several heavy upper drawers of the cabinet simultaneously.
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.