5. How much does a 20 m x 10 m x 8 m swimming pool filled with water weigh? Assume that water has a density of 62 kg/m².
2 answers:
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Answer: a. Frequency. 20, 4, 3, 1, 1, 0, 1
Explanation:
Interval(Height in feet) - - - - - - - - frequency
14000 - 14999 - - - - - - - - - - - - - - - 20
15000 - 15999 - - - - - - - - - - - - - - - 4
16000 - 16999 - - - - - - - - - - - - - - - 3
17000 - 17999 - - - - - - - - - - - - - - - 1
18000 - 18999 - - - - - - - - - - - - - - - 1
19000 - 19999 - - - - - - - - - - - - - - - 0
20000 - 20999 - - - - - - - - - - - - - - 1
Frequency : (20, 4, 3 1, 1, 0, 1)
Answer:
v = 15.8 m/s
Explanation:
Let's analyze the situation a little, we have a compressed spring so it has an elastic energy that will become part kinetic energy and a potential part for the man to get out of the barrel, in addition there is a friction force that they perform work against the movement. So the variation of mechanical energy is equal to the work of the fictional force
= ΔEm =
-Em₀
Let's write the mechanical energy at each point
Initial
Em₀ = Ke = ½ k x²
Final
= K + U = ½ m v² + mg y
Let's use Hooke's law to find compression
F = - k x
x = -F / k
x = 4400/1100
x = - 4 m
Let's write the energy equation
fr d = ½ m v² + mgy - ½ k x²
Let's clear the speed
v² = (fr d + ½ kx² - mg y) 2 / m
v² = (40 4.00 + ½ 1100 4² - 60.0 9.8 2.50) 2/60.0
v² = (160 + 8800 - 1470) / 30
v = √ (229.66)
v = 15.8 m/s