Answer:
ρ_body = 1000 kg / m³
Explanation:
This is an exercise in fluid mechanics, specifically we must use the Archimedean principle, which states that the thrust is equal to the weight of the dislodged liquid.
In this case let's start by finding the volume of our body
oak block
v = l to h
v = 0.02 0.02 0.05
V = 2 10⁻⁵ m³
cooper block indicate that it has the same dimensions so its volume is the same, the total volume of the body is
V_total = 4 10⁻⁵ m³
as they indicate that the body is fully submerged there is a balance between weight and thrust
B - W = 0
the push is
B = ρ_fluid g V_total
the body weight is
ρ_body = M / V_total
M = ρ_body V_total
W = Mg
W = ρ_body V_total g
we substitute
ρ_fluid g V_total = ρ_body V_total g
ρ_body = ρ_fluid
in this case the body is in equilibrium in the fluid, in case the density of the body is greater than that of the fluid, the body sinks
Therefore the average density is equal to the density of the fluid, since since it is water the density is
ρ_body = 1000 kg / m³
The speed of the boy and his friend at the bottom of the slope is 16.52 m/s.
<h3>Their speed at the bottom</h3>
Apply the principle of conservation of energy,
E(up) - E(friction) = E(bottom)
mg sin(15) + ¹/₂(M + m)u² - μ(M + m)cos 15 = ¹/₂(M + m)v²
![v = \sqrt{2[\frac{mgd \ sin15 \ + \frac{1}{2}(M + m)u^2 \ -\mu (M + m)g cos\ 15 }{M + m}] }](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B2%5B%5Cfrac%7Bmgd%20%5C%20sin15%20%5C%20%2B%20%5Cfrac%7B1%7D%7B2%7D%28M%20%2B%20m%29u%5E2%20%5C%20-%5Cmu%20%28M%20%2B%20m%29g%20cos%5C%2015%20%7D%7BM%20%2B%20m%7D%5D%20%7D)
where;
- u is the speed of the after 28 m
u = √2gh
u = √(2gL sin15)
u = √(2 x 9.8 x 28 x sin 15)
u = 11.92 m/s
![v = \sqrt{2[\frac{(30)(9.8)(70) \ sin15 \ + \frac{1}{2}(30 + 50)(11.92)^2 \ - 0.12 (30 + 50)9.8 cos\ 15 }{30 + 50}] }\\\\v = 16.52 \ m/s](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B2%5B%5Cfrac%7B%2830%29%289.8%29%2870%29%20%5C%20sin15%20%5C%20%2B%20%5Cfrac%7B1%7D%7B2%7D%2830%20%2B%2050%29%2811.92%29%5E2%20%5C%20-%200.12%20%2830%20%2B%2050%299.8%20cos%5C%2015%20%7D%7B30%20%2B%2050%7D%5D%20%7D%5C%5C%5C%5Cv%20%3D%2016.52%20%5C%20m%2Fs)
Thus, the speed of the boy and his friend at the bottom of the slope is 16.52 m/s.
Learn more about speed here: brainly.com/question/6504879
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Answer:
32 m and -2.4 m/s
Explanation:
Given:
v₀ = 25 m/s
t = 2.8 s
a = -9.8 m/s²
Find: Δy, v
Δy = v₀ t + ½ at²
Δy = (25 m/s) (2.8 s) + ½ (-9.8 m/s²) (2.8 s)²
Δy = 31.6 m
v = at + v₀
v = (-9.8 m/s²) (2.8 s) + 25 m/s
v = -2.44 m/s
Rounded to two significant figures, the bullet reaches a height of 32 m and a velocity of -2.4 m/s.
Answer:
For 6 its D
For 7 its A
For 8 its C
For 9 I think its B but Im not sure
Answer:
-0.55m/s
Explanation:
Given that: For the boy
Weight = 745N
Velocity = +0.35 m/s
Mass of the boy = ?
g = 9.81m/s^2
W = mg
745 = m×9.81
m = 75.94kg
For the girl
Given that:
Weight = 477 N
g = 9.81m/s^2
m = ?
W = mg
477 = m×9.81m/s^2
m = 48.62kg
To solve for the v of the girl, the two has to add up
48.62kg×v + 75.94kg×+0.35 m/s = 0
48.62v + 26.579 = 0
48.62v = - 26.579
v = -26.579/48.62
v = -0.5466
v = -0.55m/s
Hence, the velocity of the girl is -0.55m/s.
The negative sign is as a result of the two of them moving is opposite direction.