This is for grade 11

2. Noise cancellation headphones are used by pilots to protect their hearing and allow for better communication, Explain briefly how these headphones work. (27) 3. You sound two tuning forks together. One has a frequency of 300Hz, the other a frequency of 302 Hz. What do you hear? Explain why. (27) 4. The engine of a Grand Prix race car sounds different as it approaches you than when it is moving away from you. Explain why. (2) 5. Discuss the two perspective of the following statement: "If a tree falls in the forest and no one is there to hear it, it makes no sound." (27)