Question 1: Define latent heat and explain its significance during the melting of ice in sports activities.

Answer: Latent heat is the energy required to change the phase of a substance without changing its temperature. In sports, it explains how ice absorbs heat to melt, cooling athletes or equipment without increasing temperature.

Question 2: Describe what happens at the particle level during the melting of ice, focusing on energy transfer.

Answer: Particles in the ice absorb energy, which causes them to vibrate more until they overcome forces holding them together, resulting in a phase change from solid to liquid without temperature change.

Question 3: In the context of sports science, why is understanding latent heat important for athletes using ice packs?

Answer: Because it explains how ice packs absorb heat to melt, providing cooling without increasing in temperature, which helps reduce inflammation and muscle soreness.

Question 1: Calculate the amount of heat energy needed to melt 500 g of ice at 0°C. (Latent heat of fusion of ice = 334 kJ/kg).

Answer: Q = m × L = 0.5 kg × 334 kJ/kg = 167 kJ

Question 2: How much heat energy is required to convert 200 g of water at 100°C into steam at 100°C? (Latent heat of vapourisation of water = 2257 kJ/kg).

Answer: Q = 0.2 kg × 2257 kJ/kg = 451.4 kJ

Question 1: Describe a simple experiment to demonstrate the absorption of latent heat during melting, including variables to control and safety precautions.

Answer: Place a known mass of ice in a controlled environment and measure the time taken to melt at a constant temperature. Variables include ice mass, temperature, and insulation. Safety precautions involve handling ice carefully to prevent frostbite and ensuring a safe workspace.

Question 1: An athlete applies an ice pack weighing 250 g to an inflamed area. If the ice absorbs 83.5 kJ of heat during melting, what is the approximate temperature change of the body tissue if no heat loss occurs? (Specific heat capacity of tissue ≈ 3500 J/kg°C).

Answer: Q = mcΔT → ΔT = Q / (m × c) = 83,500 J / (0.25 kg × 3500 J/kg°C) ≈ 9.6°C

Question 1: Explain how the concept of latent heat is utilised in the design of cooling vests for athletes.

Answer: Cooling vests contain materials that absorb heat through phase changes, such as melting or vapourising, providing prolonged cooling without increasing temperature.

Question 2: Identify one technological advancement in sports equipment that relies on the principles of latent heat and briefly describe it.

Answer: Phase change materials embedded in sports gear, such as cooling pads, absorb and release heat during phase changes, maintaining optimal temperature during physical activity.