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Dmitry_Shevchenko [17]
3 years ago
11

An 8 kg box is at rest and is pushed for 10 m with a 60 N force. If it's accelerated to 10 m/s, calculate the efficiency of the

force.
Mathematics
1 answer:
wlad13 [49]3 years ago
4 0

Answer:

  2/3

Step-by-step explanation:

The work done on the box is ...

  Fd = (60 N)(10 m) = 600 N·m = 600 J

The amount of energy the box has as a result is ...

  KE = 1/2mv² = (1/2)(8 kg)(10 m/s)² = 400 kg·m²/s² = 400 J

The ratio of box energy to energy input is ...

  η = (400 J)/(600 J) = 2/3 . . . ≈ 66.7%

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Will mark brainliest! Questions are in the picture!
alexdok [17]

Answer:

52.9 inches .

Step-by-step explanation:

Given that the triangular indentation has an area of 100 in.² and the base and height of this traingle are represented by expressions 3x and x+3 respectively . We need to find out the <u>perimeter </u>to the nearest tenth.

As we know that the area of triangle is ,

\rm\longrightarrow Area_{\triangle}=\dfrac{1}{2}(base)(height)

Substituting the respective values,

\rm\longrightarrow 100\ =\dfrac{1}{2}(x+3)(3x)\\\\\rm\longrightarrow 2(100) = 3x(x+3)\\\\\rm\longrightarrow200 = 3x^2+9x\\\\\rm\longrightarrow 3x^2+9x-200=0

On using the <u>Quadratic</u><u> formula</u> , we have;

\rm\longrightarrow x =\dfrac{-9\pm\sqrt{9^2-4(3)(-200)}}{2(3)} \\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{81+1200}}{6}\\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{1281}}{6}

On simplifying above , we will get ,

\rm\longrightarrow x = 6.802,-9.802

Since sides can't be negative, therefore,

\rm\longrightarrow\underline{\underline{ x =6.802}}

Therefore ,

  • \rm\longrightarrow Base = 3x =3(6.802)in = 20.406\ in\\
  • \rm\longrightarrow Height = x +3=6.802+3=9.802\ in

Next let's find out the <u>hypotenuse </u>using Pythagoras theorem, as ;

\rm\longrightarrow h=\sqrt{ b^2+p^2}\\

\rm\longrightarrow h =\sqrt{ (20.406)^2+(9.802)^2}\\

\rm\longrightarrow h =\sqrt{416.40+96.07}\\

\rm\longrightarrow h = 22.63\ in

Now we may find perimeter as ,

\rm\longrightarrow P = p + b + h \\

\rm\longrightarrow P = (22.63 + 9.802 + 20.406)in.

\\\rm\longrightarrow P = 52.89 \ in.\\

\rm\longrightarrow \underline{\underline{ Perimeter = 52.9\ in .}}

8 0
3 years ago
Add the Following Fractions:
Sergio039 [100]

Answer: C, 3/4 And it's decimal form is 0.75

Step-by-step explanation:

8 0
2 years ago
BRAINLIEST IF RIGHT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Trevon's Custom Kitchen Supplies sells handmade forks an
AURORKA [14]

Answer:

D. 9 forks and 6 spoons

Step-by-step explanation:

Let's calculate how many forks and spoons were made.  We need to guess a pair of variable values that will add up to $24.60.  We'll do this by substituting all the possible pairs in:

Here's the pair for A:

[($1.80 * a) + ($1.40 * b)]

= [($1.80 * 8) + ($1.40 * 10)]

= [$14.40 + $14]

= $28.40

Is $28.40 equal to $24.60? No, this is not correct.

Here's the pair for B:

[($1.80 * a) + ($1.40 * b)]

= [($1.80 * 8) + ($1.40 * 8)]

= [$14.40 + $10.80]

= $25.20

Is $25.20 equal to $24.60? No, this is not correct.

Here's the pair for C:

[($1.80 * a) + ($1.40 * b)]

= [($1.80 * 9) + ($1.40 * 9)]

= [$16.20 + $12.60]

= $28.80

Is $28.80 equal to $24.60? No, this is not correct.

Here's the pair for D:

[($1.80 * a) + ($1.40 * b)]

= [($1.80 * 9) + ($1.40 * 6)]

= [$16.20 + $8.40]

= $24.60

Is $24.60 equal to $24.60? Yes, this is correct.

Therefore, we know the answer is (D) 9 forks and 6 spoons

We can also check by substituting these values to find the amount Trevon's Custom Kitchen Supplies earned last April:

[($4.60 * a) + ($5.40 * b)]

= [($4.60 * 9) + ($5.40 * 6)]

= [$41.40 + $32.40]

= $73.80

This is equal to the amount of money earned last April.

I hope this helps! Tell me if I'm wrong, please!

4 0
3 years ago
A hemispherical tank is filled with water and has a diameter of 12 feet. If water weighs 62.4 pounds per cubic foot, what is the
Reil [10]

   Answer:

The total weight = 1286 × 62.4 = 80246 pounds.

Step-by-step explanation:

The formula of the volume of the sphere is

V = 4/3×π×r³

Given

d = 17 feet

d = 2r

r = d/2 = 17/2 = 8.5 feet

V = 4/3×π×r³

Since we need half of the volume as it is a hemispherical tank.

= 1286 ft³

Given that the weighs 62.4 pounds per cubic foot

Thus,  the total weight = 1286 × 62.4 = 80246 pounds.            

6 0
3 years ago
What is the difference in the account balances shown below? Behrooz: (-$21.00) Cody: $3.00
suter [353]

Answer:

-7

Step-by-step explanation:

-21.00/3.00

4 0
2 years ago
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