Answer:
they were hunter gatherers
Explanation:
Answer:
Evolutionary
Explanation:
Because our ancestors were afraid of these poisonous spiders and snakes which lead to them to telling their kids of these dangers. Their kids will fear them without even encountering any and this will also be passed on to their future generations.
heat from water goes into air in ball
air expands
ping goes the dent
Answer:
1) The speed of sound increases
2) 440 Hz
3) 29°C
4) 17°C
5) 434 Hz
6) 12 m/s
7) 17.3 m
Explanation:
1) The speed of sound increases
2) V = f×λ
f = V/λ = 343/0.78 = 439.744 ≈ 440 Hz
3) V = f×λ
512 × 0.68 = 348.16 m/s
348.16 - 331 = 17.16
T = 17.16/0.6 = 28.6 ≈ 29°C
4) Increase in speed = 350 - 340 = 10
Increase in temperature = 10/0.6 = 16.67° ≈ 17°C
5) f = V/λ = 343/0.79 = 434 Hz
6) 331 + 0.6×30 - (331 × 0.6 ×10) = 12 m/s
7) V = 331 + 0.6×25 = 346m/s
λ = 346/20 = 17.3 m