Physics 5054 · O Level · Balanced and unbalanced forces
Balanced and unbalanced forces — practice question
A sky-diver leaps out of a balloon that is stationary. At the start, his downward acceleration is $10\,\text{m s}^{-2}$. Fig. 1.1 indicates the directions of the sky-diver’s weight and the air resistance. The sky-diver has a mass of $60\,\text{kg}$ and a weight of $600\,\text{N}$.
(a)[2]
Explain, in terms of the forces, why his initial downward acceleration is $10\,\text{m s}^{-2}$.
(b)[1]
After the parachute opens, the sky-diver undergoes upward acceleration briefly. Explain why.
(c(i))[1]
Using Fig. 1.2, determine the sky-diver’s terminal velocity.
(c(ii))[1]
Calculate the resultant force acting on the sky-diver when his speed is $5.5\,\text{m s}^{-1}$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Air resistance is zero / negligible (at the start) or weight is much greater than air resistance” …