(a)[2]
Complete Fig. 1.1 by placing a tick (✓) in the correct column to show whether each listed quantity is a scalar or a vector.
(b)
A floating sphere is held by a cable attached to the bottom of a river, as shown in Fig. 1.2. The sphere is in equilibrium, with the cable making an angle of $75^{\circ}$ to the horizontal. Take the force on the sphere due to the water flow to be horizontal. The sphere has radius $23\,\text{cm}$. It is solid and made from a material with density $82\,\text{kg m}^{-3}$.
(b(i))[2]
Show that the sphere has weight $41\,\text{N}$.
(b(ii))[2]
The cable tension is $290\,\text{N}$. Determine the upthrust on the sphere.
(b(iii))[1]
Explain the cause of the upthrust on the sphere.