Part (a)
Let h = depth of water surface from the top of the well, m
Because the stone is dropped, its initial velocity is zero.
Let t₁ = time for the stone to drop, s
Then
h = (1/2)*(9.8 m/s²)*(t₁ s)²
t₁ = √(h/4.9) s = 0.4518√h s
The velocity of sound is 336 m/s.
The time for the sound wave to travel from the water surface to the top of the well is
t₂ = h/336 m/s
Because the time before the sound is heard is 2.4 s, therefore
t₁ + t₂ = 2.4
0.45181√h + h/336 = 2.4
Multiply through by 336.
151.8082√h + h = 806.4
h - 806.4 = -151.8082√h
h² - 1612.8h + 6.5028 x 10⁵ = 2.3046 x 10⁴h
h² - 2.4659 x 10⁴h + 6.5028 x 10⁵ = 0
Solve with the quadratic formula.
h = 0.5[2.4659 x 10⁴ +/- 2.4606 x 10⁴]
= 24632 m or 26.5 m
Test the two answers.
When h = 24632,
t₁ = 0.4518√(24632) = 70.9 s (Not acceptable)
When h = 26.5 m,
t₁ = 0.4518√(26.5) = 2.3258 s, t₂ = 26.5/336 = 0.0789 s,
t₁+t₂ = 2.4 s (CORRECT)
Answer: h = 26.5 m
Part (b)
If travel time for the sound is ignored, then
0.4518√h = 2.4
h = (2.4/0.45118)² = 28.2 m
The percent error is 100*[(28.2 - 26.5)/26.5] = 6.42%
Answer: The error is 6.4%
Increased the temperature in the room, which means an increase in the airs connect molecular energy
Answer:
because of Gravity
Explanation:
The Sun's gravity pulls on the planets, just as Earth's gravity pulls down anything that is not held up by some other force and keeps you and me on the ground.
Increases exponentially is your correct answer
Answer:
2
Explanation:
Step 1: RxN
4Al + 3O₂ → Al₂O₃
Step 2: Balance RxN
We have 4 Al's and 6 O₂'s on the reactant side.
We need the same number of Al's and O₂'s on the product side.
4Al + 3O₂ → 2Al₂O₃
