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Oliga [24]
3 years ago
13

Explain how improving the EXERGY may be as good, if not better than discovering new/coal mines ? (10 marks)

Physics
1 answer:
Reptile [31]3 years ago
3 0

Answer:

Improving energy is more good than discovering coal mines

Explanation:

It is because discovering coal mines can destroy a land by making deep holes and can even destroy some animal's habitat but by improving energy none of this will happen.

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Determine the change in velocity of a car that starts at rest and has a final velocity of 20 miles per second North
Katen [24]

Answer: The change in velocity is 20mph

Explanation: The change in velocity is the difference between the final velocity and the initial velocity.

The initial velocity is 0 and the final velocity is 20mph.

Using the formula dV=Vf-Vi

dV=20-0

dV=20mph North

5 0
4 years ago
Calculate the acceleration if you push with a 20-N horizontal force on a 2-kg block on a horizontal friction-free air table
Afina-wow [57]
Acceleration = force / mass = 20 / 2 = 10 m/s^2
3 0
3 years ago
Help with these please someone?
DIA [1.3K]

Answer:

8. 2.75·10^-4 s^-1

9. No, too much of the carbon-14 would have decayed for radiation to be detected.

Explanation:

8. The half-life of 42 minutes is 2520 seconds, so you have ...

1/2 = e^(-λt) = e^(-(2520 s)λ)

ln(1/2) = -(2520 s)λ

-ln(1/2)/(2520 s) = λ ≈ 2.75×10^-4 s^-1

___

9. Reference material on carbon-14 dating suggests the method is not useful for time periods greater than about 50,000 years. The half-life of C-14 is about 5730 years, so at 65 million years, about ...

6.5·10^7/5.73·10^3 ≈ 11344

half-lives will have passed. Whatever carbon 14 may have existed at the time will have decayed completely to nothing after that many half-lives.

7 0
3 years ago
A pirate fires his cannon parallel to the water but 3.5 m above the water. The cannonball leaves the cannon with a velocity of 1
Bumek [7]

Answer:

202.8m

Explanation:

Given that A pirate fires his cannon parallel to the water but 3.5 m above the water. The cannonball leaves the cannon with a velocity of 120 m/s. He misses his target and the cannonball splashes into the briny deep.

First calculate the total time travelled by using the second equation of motion

h = Ut + 1/2gt^2

Let assume that u = 0

And h = 3.5

Substitute all the parameters into the formula

3.5 = 1/2 × 9.8 × t^2

3.5 = 4.9t^2

t^2 = 3.5/4.9

t^2 = 0.7

t = 0.845s

To know how far the cannonball travel, let's use the equation

S = UT + 1/2at^2

But acceleration a = 0

T = 2t

T = 1.69s

S = 120 × 1.69

S = 202.834 m

Therefore, the distance travelled by the cannon ball is approximately 202.8m.

4 0
3 years ago
A laser beam with a frequency of 180 Hz forms an 8 m standing wave with 10 nodes.
DIA [1.3K]

Answer:33

Explanation:

F = frequency

N =  Node count

w = wave lenght

v = wave velocity

L = distance wave traveled

First find wave length of laser

w = (2/(N))*(L)

w = (2/(10))*(8)

w = 1.6

then using (w), find velocity

V =  (w)(F)

V = (1.6)*(108)

V = 288

Plug in V and the new frequency to solve for new node count

F = NV/2L

(600) = (N)*(288) / 2 * (8)

(N) = 33.33

there are 33 nodes

8 0
3 years ago
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