The diagram shows an athlete doing press-ups on a floor. The athlete is using both hands. The area of contact of each hand with the floor is S. The athlete's toes act as a pivot during each press-up. The athlete's weight W acts through point X. The distance between his toes and point X is three quarters of the distance between his toes and his shoulders. What is the pressure exerted on the palm of each of the athlete's hands?

Four identical measuring cylinders contain liquid. Two contain water of density 1000 kg/m³. Two contain paraffin of d…

A steel ball is released just below the surface of thick oil in a cylinder. During the first few centimetres of trave…

A hard stone hits the ground and comes to rest almost immediately. As the stone hits the ground, what is the directio…

A capacitor C charges when it is connected to a d.c. power supply. Which arrows show the direction of the conventiona…

In one radioactive decay, radium (Ra) gives rise to radon (Rn) as shown. ²²⁶Ra → ²²²Rn ⁸⁸ ⁸⁶ What particle is also pr…

Which row is correct for fission and for fusion?