1) The diagram below shows the forces acting on an aeroplane.

Which of the following is correct when the aeroplane is descending with a constant horizontal speed and an increasing vertical speed?

2) The diagram below shows several forces acting on an object.

What is the net force acting on the object?

3) Which of the following cannot be the magnitude of the resultant force when two forces of magnitudes 7.0 N and 13.0 N act on an object?

4) A parachutist opens a parachute and an upward force acts on it. The mass of the parachutist and parachute are 50.0 kg and 5.0 kg respectively.

The parachutist and parachute accelerate downwards at 1.0 m s^-2.
What is the total air resistance acting on them?

5) Only 2 forces act on an object. If the object is in equilibrium, which of the following condition(s) is/are required?

(1) The 2 forces are of the same magnitude.
(2) The 2 forces act in opposite directions.
(3) The 2 forces act in the same direction.
(4) The 2 forces are of the same nature.