Question 1: Define a free body diagram and explain its purpose in analysing forces acting on an object.

Answer: A free body diagram is a graphical representation showing all the forces acting on an object, used to analyse the net force and resulting motion.

Question 2: List three common forces that can act on an object resting on a surface.

Answer: Normal force, gravitational force (weight), frictional force.

Question 3: Explain how the normal force differs from the gravitational force in the context of a free body diagram.

Answer: The normal force acts perpendicular to the surface supporting the object, balancing the component of weight perpendicular to the surface, while gravitational force acts vertically downward due to gravity.

Question 1: A box of mass 10 kg rests on a horizontal surface. The coefficient of kinetic friction between the box and the surface is 0.3. Calculate the maximum force of applied horizontal force that can be exerted without moving the box. Use g = 9.8 m/s². Show your working.

Answer: F = μ × N = μ × m × g = 0.3 × 10 × 9.8 = 29.4 N

Question 2: A 5 kg object is pulled with a force of 20 N across a rough surface. If the acceleration of the object is 2 m/s², calculate the total resistive force acting on it using Newton's second law.

Answer: F_resistive = F_applied - m × a = 20 - 5 × 2 = 10 N

Question 1: Describe a simple experiment to demonstrate the effect of friction on an object sliding down an inclined plane. Include the main variables to control and measure.

Answer: Use an inclined plane with adjustable angle, measure the time taken for a block to slide, control the surface type, block mass, and angle; measure the force needed to move the block at different angles.

Question 2: Identify three safety precautions to consider when experimentally analysing forces acting on objects.

Answer: Ensure objects are securely attached, avoid overloading force measuring devices, and keep the work area clear of obstructions.

Question 1: A 15 kg object is suspended from a ceiling and has a tension of 150 N in the supporting cable. Analyse the forces acting on the object and determine if the object is in equilibrium.

Answer: Weight = m × g = 15 × 9.8 = 147 N; Tension = 150 N; Since Tension > weight, the object is accelerating upwards; therefore, it is not in equilibrium.

Question 2: A car of mass 1200 kg accelerates at 2.5 m/s² along a level road. Using Newton's second law, calculate the net force acting on the car.

Answer: F = m × a = 1200 × 2.5 = 3000 N

Question 1: Explain how free body diagrams are used in the design of safety harnesses for rock climbers.

Answer: They help analyse the forces during a fall, ensuring the harness and anchor points can withstand maximum forces, preventing failure.

Question 2: Describe how understanding forces and free body diagrams can improve the efficiency of a vehicle’s suspension system.

Answer: By analysing forces acting on the vehicle, engineers can optimise shock absorber design to better absorb road shocks, improving ride comfort and safety.