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 diagram that shows all the forces acting on an object as vectors originating from a single point. Its purpose is to visualise and analyse the forces to understand the object's motion or equilibrium.

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

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

Question 1: A box with a mass of 10 kg is pushed across a horizontal surface with a force of 40 N. The frictional force opposing the movement is 10 N. Calculate the net force acting on the box and its acceleration. (Use g = 9.8 m/s²)

Answer: Net force = Applied force - Frictional force = 40 N - 10 N = 30 N; Acceleration = Net force / mass = 30 N / 10 kg = 3 m/s².

Question 2: A 5 kg object is hanging from a crane. What is the tension in the cable if the object is stationary?

Answer: Tension = weight = mass × gravity = 5 kg × 9.8 m/s² = 49 N.

Question 1: Outline the procedure you would follow to measure the frictional force acting on a block sliding on a horizontal surface. Include at least two safety precautions.

Answer: To measure the frictional force, place the block on the surface and attach a force sensor or use a spring scale. Gradually apply a horizontal force until the block just starts to move. Record the force at this point as the maximum static friction. To ensure safety, keep hands clear of moving parts and ensure the surface is stable to prevent slipping or falling.

Question 1: A car of mass 1500 kg is moving at a constant speed on a level road. The engine provides a driving force of 3000 N. Assuming steady motion, what is the opposing frictional force acting on the car?

Answer: The opposing frictional force equals the driving force, so 3000 N, since the car moves at constant speed and acceleration is zero.

Question 2: Explain why the net force on a skydiver in free fall is not zero, even though the skydiver is falling at terminal velocity.

Answer: At terminal velocity, the upward air resistance balances the downward gravitational force, so the net force is zero, and the skydiver falls at constant speed. Before reaching terminal velocity, the net force is downward, causing acceleration.

Question 1: Describe how understanding free body diagrams can help engineers in designing safer car braking systems.

Answer: Engineers use free body diagrams to analyse the forces acting on a vehicle during braking, such as friction and normal force, to ensure the braking system can generate sufficient force to stop the car safely within a certain distance.

Question 2: In the design of suspension systems in bicycles, how does analysing forces with free body diagrams improve performance and safety?

Answer: Analyzing forces helps in understanding how loads are distributed through the suspension, ensuring it absorbs shocks effectively, maintains stability, and prevents structural failure, thereby improving safety and ride quality.