Question 1: Define momentum in physics and state its SI unit.

Answer: Momentum is the product of an object's mass and its velocity; its SI unit is kilogram metre per second (kg·m/s).

Question 2: Explain why a heavy moving object has more momentum than a lighter object moving at the same velocity.

Answer: Because momentum depends on mass, a heavier object has a greater momentum than a lighter one moving at the same velocity.

Question 1: A car with a mass of 1200 kg is moving at a velocity of 15 m/s. Calculate its momentum.

Answer: p = 1200 kg × 15 m/s = 18,000 kg·m/s

Question 2: An ice hockey puck has a mass of 0.16 kg and is sliding at a velocity of 20 m/s. What is its momentum?

Answer: p = 0.16 kg × 20 m/s = 3.2 kg·m/s

Question 1: Describe an experiment to investigate how the mass of a moving object affects its momentum. Include the variables you would control and measure, and safety precautions.

Answer: Students could use a track and a trolley of different masses, measuring the velocity with a motion sensor or stopwatch. Control variables include the initial push and track friction. Measure the momentum by calculating mass × velocity for each trolley. Safety precautions include ensuring the track is secure and students stand clear during motion.

Question 2: Identify three variables that could affect the outcome of an experiment measuring the change in momentum during a collision, and suggest how to control them.

Answer: Variables include the mass of the objects, initial velocity before collision, and the surface friction. Control by using objects of known mass, ensuring consistent initial velocities, and conducting experiments on a smooth, level surface.

Question 1: A 0.5 kg ball moving at 4 m/s collides with a stationary 1 kg ball. After the collision, the 0.5 kg ball slows down to 2 m/s. Assuming a perfectly elastic collision and that the 1 kg ball moves after the collision, explain how the conservation of momentum applies and estimate the velocity of the 1 kg ball after the collision.

Answer: Total initial momentum = 0.5 kg × 4 m/s + 1 kg × 0 = 2 kg·m/s. Final momentum of 0.5 kg ball = 0.5 kg × 2 m/s = 1 kg·m/s. To conserve momentum, the 1 kg ball must have momentum = 1 kg·m/s, so its velocity after collision is 1 kg·m/s ÷ 1 kg = 1 m/s in the same direction.

Question 1: Explain how understanding momentum is important in the design of safety features in cars, such as crumple zones and airbags.

Answer: Understanding momentum helps engineers design features that reduce the force during a collision by increasing the impact time, thereby decreasing injury risk. Crumple zones and airbags absorb and dissipate momentum, protecting passengers.

Question 2: Describe how the principle of conservation of momentum is utilised in space exploration, such as satellite deployment or rocket propulsion.

Answer: Spacecraft use the conservation of momentum in rocket propulsion, where expelling fuel at high velocity in one direction causes the rocket to move in the opposite direction. Similarly, satellite deployment uses momentum principles to ensure controlled movement and placement in orbit.