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A man uses a dog whistle to call his dog - Edexcel - GCSE Physics - Question 4 - 2014 - Paper 1
Question 4
A man uses a dog whistle to call his dog. The whistle uses ultrasound. (i) The dog can hear the whistle but the man cannot. Explain why the dog can hear the whistle... show full transcript
Worked Solution & Example Answer:A man uses a dog whistle to call his dog - Edexcel - GCSE Physics - Question 4 - 2014 - Paper 1
Step 1
Explain why the dog can hear the whistle but the man cannot.
Answer
The dog can hear the whistle because it produces sound at a frequency above 20,000 Hz, which is classified as ultrasound. Humans typically cannot hear sounds above this frequency, which explains why the man cannot perceive the whistle.
Step 2
Calculate the speed of ultrasound.
Answer
To find the speed of ultrasound, we use the formula:
ext{Speed} = rac{ ext{Distance}}{ ext{Time}}Substituting the values into the equation:
ext{Speed} = rac{140 ext{ m}}{0.42 ext{ s}} \ = 333.33 ext{ m/s}Thus, the speed of ultrasound is 330 m/s, rounded to the nearest whole number.
Step 3