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sergeinik [125]
3 years ago
8

Which of these statements are true about hydroelectric power? Check all that are true. It is the most widely used renewable ener

gy source in the world. It never disrupts ecosystems. It is not always available. A hydroelectric dam controls the force of moving water to generate electricity.
Physics
1 answer:
IRINA_888 [86]3 years ago
7 0

Answer:

the last one is triu!!!!!!

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What is the equation for horizontal velocity
yan [13]
V(x) = V(ix)
v=d/delta t
3 0
3 years ago
A 25 kg bear slides, from rest, 12 m down a lodgepole pine tree, moving with a speed of 5.6 m/s just before hitting the ground.
Anuta_ua [19.1K]

Answer:

(A) -2940 J

(B) 392 J

(C) 212.33 N

Explanation:

mass of bear (m) = 25 kg

height of the pole (h) = 12 m

speed (v) = 5.6 m/s

acceleration due to gravity (g) = 9.8 m/s

(A) change in gravitational potential energy (ΔU) = mg(height at the bottom- height at the top)

height at the bottom = 0

         = 25 x 9.8 x (0-12) = -2940 J

(B) kinetic energy of the Bear (KE) = 0.5mv^{2}

           = 0.5 x 25 x 5.6^{2}  = 392 J

(C) average frictional force = \frac{change in thermal energy}{height} = \frac{-(ΔKE+ΔU)}{h}

  • change in KE (ΔKE) = initial KE - final KE
  • ΔKE = 0.5mv^{2} - 0.5mvf^{2}            
  • when the Bear reaches the bottom of the pole, the final velocity (Vf) is 0, therefore the change in kinetic energy becomes  ΔKE = 0.5x25x5.6^{2} - 0 = 392 J

 \frac{-(ΔKE+ΔU)}{h}[/tex] = \frac{-(392 + (-2940))}{12}

=  \frac{(-392 + 2940)}{12} = 212.33 N

5 0
3 years ago
Which of the following best defines insulator?
Leya [2.2K]

Answer:a substance with low ability or no ability to conduct energy

Explanation:

6 0
3 years ago
An organism is composed of several organ systems. Often, the different organ systems work together towards a common purpose. For
Gemiola [76]

Answer:

Skeletal system, muscular system

Explanation:

Skeletal system:

bones

Muscular system:

muscles

Together, they work together and create the musculoskeletal system.

4 0
3 years ago
Read 2 more answers
Could I please get some help on this question I don’t understand .
Oksana_A [137]

Answer:

12.5 m/s

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 0 m/s

Height (h) = 8 m

Final velocity (v) at 8 m above the lowest point =?

NOTE: Acceleration due to gravity (g) = 9.8 m/s²

The velocity of the roller coaster at 8 m above the lowest point can be obtained as follow:

v² = u² + 2gh

v² = 0² + (2 × 9.8 × 8)

v² = 0 + 156.8

v² = 156.8

Take the square root of both side

v = √156.8

v = 12.5 m/s

Therefore, the velocity of the roller coaster at 8 m above the lowest point is 12.5 m/s.

5 0
3 years ago
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