Rahim is watching his favorite football team on television. In order to work, the television must be

In your own words, explain why sinkholes are very common in Florida. List one use of sinkholes in Florida.

melamori03 [73]

Florida's peninsula is made up of porous carbonate rocks such as limestone When the dirt, clay or sand gets too heavy for the limestone roof, it can break and form a sinkhole. Sinkholes are caused naturally.

dont use my words put this in your own hope it helps you understand it better

8 0

3 years ago

Read 2 more answers

Firemen are shooting a stream of water at a burning building. A high-pressure hose shoots out the water with a speed of 26.0 m/s

alekssr [168]

Answer:

a) θ = 58.3º

b) vfh = 13.7 m/s

c) g = -9.8 m/s2

d) h = 22.2 m

e) vfb = 15.5 m/s

Explanation:

a)

Assuming that gravity is the only influence that causes an acceleration to the water, due to it is always downward, since both directions are independent each other, in the horizontal direction, the water moves at a constant speed.
Since the velocity vector has a magnitude of 26.0 m/s, we can find its horizontal component as follows:
vₓ₀ = v * cos θ (1)
where θ is the angle between the water and the horizontal axis (which we define as the x-axis, being positive to the right).
Applying the definition of average velocity, taking the end of the hose like the origin, and making t₀ = 0, we can write the following expression:

$x_{f} = v_{ox} * t = v_{o} * cos \theta * t (2)$

Replacing by the givens of xf = 41.0m, t = 3.00 s, and v=26.0 m/s, we can solve for the angle of elevation θ, as follows:

$cos \theta = \frac{x_{f} }{v*t} = \frac{41.0m}{26.0m/s*3.00s} = 0.526 (3)$

⇒θ = cos⁻¹ (0.526) = 58.3º (4)

b)

At the highest point in its trajectory, just before starting to fall, the vertical component of the velocity is just zero.
Since the horizontal component keeps constant during all the journey, we can conclude that the speed at this point is just v₀ₓ, that we can find easily from (1) replacing by the values of v and cos θ, as follows:
vₓ₀ = v * cos θ = 26.0 m/s * 0.526 = 13.7 m/s. (5)

c)

At any point in the trajectory, the only acceleration present is due to the action of gravity, which accepted value is -9.8 m/s2 (taking the upward direction on the vertical y-axis as positive)

d)

Since we know the time when the water strikes the building, it will be the same for the vertical movement, so, we can use the kinematic equation for vertical displacement, as follows:

$\Delta y = v_{oy} * t - \frac{1}{2} *g*t^{2} (6)$

Our only unknown remains v₀y, which can be obtained in the same way than the horizontal component:
v₀y = v * sin θ = 26.0 m/s * 0.85 = 22.1 m/s (7)
Replacing (7) in (6), we get:

$\Delta y = 22.1 m/s* 3.0s - \frac{1}{2} *9.8m/s2*(3.00s)^{2} = 22.2 m (8)$

e)

When the water hits the building the velocity vector, has two components, the horizontal vₓ and the vertical vy.
The horizontal component, since it keeps constant, is just v₀x:
v₀ₓ = 13.7 m/s
The vertical component can be found applying the definition of acceleration (g in this case), solving for the final velocity, as follows:

$v_{fy} = v_{oy} - g*t (9)$

Replacing by the time t (a given), g, and v₀y from (7), we can solve (9) as follows:

$v_{fy} = 22.1 m/s - 9.8m/s2*3.00s = -7.3 m/s (10)$

Since we know the values of both components (perpendicular each other), we can find the magnitude of the velocity vector (the speed, i.e. how fast is it moving), applying the Pythagorean Theorem to v₀ₓ and v₀y, as follows:

$v_{f} = \sqrt{(13.7m/s)^{2} +(-7.3m/s)^{2}} = 15.5 m/s (11)$

3 0

3 years ago

A passenger railroad car has a total of 8 wheels. Springs on each wheel compress--slightly--when the car is loaded. Ratings for

deff fn [24]

Answer:

Explanation:

mg = kx

x = mg/k

x = 30(80)(9.8)/2.8e7 = 0.00084 m ≈ 1 mm

5 0

3 years ago

An intergalactic rock star bangs his drum every 1.50 s. A person on earth measures that the time between beats is 2.70 s. How fa

sineoko [7]

Answer:

v = 83.1 % of speed of light

Explanation:

given,

T_e is the earth time = 2.7 s

T_s is the ship time = 1.5 s

we know,

$T_s = T_e \times \gamma$

where c is the speed of light

v is the speed of the rock star moving

$T_s = T_e\times \sqrt{1-\dfrac{v^2}{c^2}}$

$1.5= 2.7\times \sqrt{1-\dfrac{v^2}{c^2}}$

$\sqrt{1-\dfrac{v^2}{c^2}} =0.556$

squaring both side

$1-\dfrac{v^2}{c^2}=0.3086$

$v^2=0.6914c^2$

v = 0.831 c

v = 83.1 % of speed of light

7 0

3 years ago

With thermodynamics, one cannot determine ________. Question 6 options: the speed of a reaction the direction of a spontaneous r

pantera1 [17]

Answer:

A. the speed of a reaction

Explanation:

The thermodynamic aspect of a reaction will show you the energy needed for a reaction to occur. If the energy difference(ΔG) is positive, which means the reaction is absorbing energy and it called endothermically. The opposite will be an exothermic reaction that will release energy, which means it doesn't need energy and the energy difference (ΔG) will be negative.

Thermodynamic can be used to determine a few things of a reaction, like the direction of the reaction, the extent, or temperature in which the reaction is spontaneous. But thermodynamic not used to find the speed of a reaction.

3 0

4 years ago