SEMI FINAL STAGE 2026
St. Augustine’s College: 52 points
Prempeh College: 47 points
Pope John SHS & Min. Sem.: 28 points
QUESTION
Find the speed of sound in air at 65.0°C.
ANSWER: $v = 3.70 \times 10^2 \text{ m/s}$
FORMULA
$v = 331 + 0.6T$
SOLUTION:
$0.6 \times 65 = \dfrac{3}{5} \times 65$
$0.6 \times 65 = 3 \times 13$
$0.6 \times 65 = 39$
$v = 331 + 39$
$v = 370 \text{ m/s}$
$v = 3.70 \times 10^2 \text{ m/s}$
ANSWER: $v = 3.70 \times 10^2 \text{ m/s}$
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PRACTICE QUESTIONS
1. QUESTION: Find the speed of sound in air at 25.0 °C.
ANSWER: 346 m/s or $3.46\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 25.0 = 15.0$
$v = 331 + 15.0$
$v = 346\text{ m/s}$
2. QUESTION: Find the speed of sound in air at 35.0 °C.
ANSWER: 352 m/s or $3.52\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 35.0 = 21.0$
$v = 331 + 21.0$
$v = 352\text{ m/s}$
3. QUESTION: Find the speed of sound in air at 45.0 °C.
ANSWER: 358 m/s or $3.58\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 45.0 = 27.0$
$v = 331 + 27.0$
$v = 358\text{ m/s}$
4. QUESTION: Find the speed of sound in air at 20.0 °C.
ANSWER: 343 m/s or $3.43\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 20.0 = 12.0$
$v = 331 + 12.0$
$v = 343\text{ m/s}$
5. QUESTION: Find the speed of sound in air at 30.0 °C.
ANSWER: 349 m/s or $3.49\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 30.0 = 18.0$
$v = 331 + 18.0$
$v = 349\text{ m/s}$
6. QUESTION: Find the speed of sound in air at 40.0 °C.
ANSWER: 355 m/s or $3.55\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 40.0 = 24.0$
$v = 331 + 24.0$
$v = 355\text{ m/s}$
7. QUESTION: Find the speed of sound in air at 10.0 °C.
ANSWER: 337 m/s or $3.37\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 10.0 = 6.00$
$v = 331 + 6.00$
$v = 337\text{ m/s}$
8. QUESTION: Find the speed of sound in air at 5.00 °C.
ANSWER: 334 m/s or $3.34\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 5.00 = 3.00$
$v = 331 + 3.00$
$v = 334\text{ m/s}$
9. QUESTION: Find the speed of sound in air at 55.0 °C.
ANSWER: 364 m/s or $3.64\times10^{2}$ m/s
SOLUTION:
$v = 331 + 0.6T$
$0.6 \times 55.0 = 33.0$
$v = 331 + 33.0$
$v = 364\text{ m/s}$