Define the term acceleration.
An Olympic diver is standing on a platform above a pool of water, as shown in Fig. 2.1. While on the platform, the diver’s centre of gravity is $9.0\,\text{m}$ above the water surface. The diver leaves the platform with a velocity of $5.9\,\text{m s}^{-1}$ at an angle of $60^\circ$ to the horizontal. Air resistance is negligible. When the diver reaches the water surface, his centre of gravity is $1.2\,\text{m}$ above the water surface. Calculate the speed of the diver at the instant he hits the surface of the water.
Describe and explain how the viscous drag force on the diver in the water varies as he moves downwards.
The diver’s volume is $7.5 \times 10^{-2}\,\text{m}^3$. The density of water is $1.0 \times 10^3\,\text{kg m}^{-3}$. Show that the upthrust on the diver when he is completely underwater is $740\,\text{N}$.
At one particular instant, when the diver is completely underwater, his horizontal velocity is zero. At that moment the viscous drag force on him is $950\,\text{N}$ upwards. The diver’s mass is $78\,\text{kg}$. Determine the magnitude and direction of the diver’s acceleration.