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3 years ago

13

what is the recommended daily dosage of flouride for a child over three years of age living in an area where drinking water is f

ree fluoride

1 answer:

Finger [1]3 years ago

7 0

<span>What is the recommended daily dosage of flouride for a child over three years of age living in an area where drinking water is free fluoride</span>child:

3-6: 0.5mg

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A basketball is shot at 14.0 m/s at a 65.0 degree angle. What is the magnitude only (no direction) of the velocity of the ball 2

Alex787 [66]

Answer:

10.4 m/s

Explanation:

I just know it's right!

8 0

3 years ago

A 0.274 kg block is pushed up a frictionless ramp inclined at angle of 32° above the horizon. The push force is a constant 2.55

SpyIntel [72]

Answer:

The answer is 2,416 m/s. Let's jump in.

Explanation:

We do work with the amount of energy we can transfer to objects. According to energy theory:

W = ΔE

Also as we know W = F.x

We choose our reference point as a horizontal line at the block's rest point.<u> At the rest, block doesn't have kinetic energy</u> and <u>since it is on the reference point(as we decided) it also has no potential energy.</u>

Under the force block gains;

W = F.x → $W=2,55.0,71=1,8105\frac{N}{m}$

In the second position block has both kinetic and potential energy. Following the law of conservation of energy;

W = ΔE = Kinetic energy + Potantial Energy

W = ΔE = $\frac{1}{2} mV^{2} + mgh$

Here we can find h in the triangle i draw in the picture using sine theorem;

In a triangle $\frac{a}{sinA}=\frac{b}{sinB}=\frac{c}{sinC}$

In our situation

$\frac{0,71}{sin90} =\frac{h}{sin32}$ → $h=0,376$

Therefore

$1,8105=\frac{1}{2} 0,274V^{2} +0,274.9,81.0,376$

→ $V=2,416$

7 0

3 years ago

A car travels 40km/hr for 2 hours and 55km/hr for 2 hours how far has the car traveled what’s its average velocity?

vfiekz [6]

Answer;

Average speed = 47.5 km/hr

Explanation and solution;

Average Speed = Total distance /Total time

Total distance;

-In the first two hours travelling at 40km/hr, total distance traveled is 80km.

(40 × 2) = 80 km

-In next two hours distance covered is 110 km. (55 ×2)

Total distance = 110 + 80 = 190 km

Total time = 2 + 2 = 4 hours

Average Speed = Total distance /Total time

= 190/4

= 47.5 km/hr

7 0

3 years ago

Two long, parallel wires carry unequal currents in the same direction. The ratio of the currents is 3 to 1. The magnitude of the

astraxan [27]

Answer:

3A is the larger of the two currents.

Explanation:

Let the currents in the two wires be I₁ and I₂

given:

Magnitude of the electric field, B = 4.0μT = 4.0×10⁻⁶T

Distance, R = 10cm = 0.1m

Ratio of the current = I₁ : I₂ = 3 : 1

Now, the magnitude of a magnetic field at a distance 'R' due to the current 'I' is given as

$B = \frac{\mu_oI}{2\pi R}$

Where $\mu_o$ is the magnitude constant = 4π×10⁻⁷ H/m

Thus, the magnitude of a magnetic field due to I₁ will be

$B_1 = \frac{\mu_oI_1}{2\pi R}$

$B_2 = \frac{\mu_oI_2}{2\pi R}$

given,

B = B₁ - B₂ (since both the currents are in the same direction and parallel)

substituting the values of B, B₁ and B₂

we get

4.0×10⁻⁶T = $\frac{\mu_oI_1}{2\pi R}$ - $\frac{\mu_oI_2}{2\pi R}$

or

4.0×10⁻⁶T = $\frac{\mu_o}{2\pi R}\times (I_1-I_2 )$

also

$\frac{I_1}{I_2} = \frac{3}{1}$

⇒ $I_1 = 3\times I_2$

substituting the values in the above equation we get

4.0×10⁻⁶T = $\frac{4\pi\times 10^{-7}}{2\pi 0.1}\times (3 I_2-I_2)$

⇒ $I_2 = 1A$

also

$I_1 = 3\times I_2$

⇒ $I_1 = 3\times 1A$

⇒ $I_1 = 3A$

Hence, the larger of the two currents is 3A

3 0

3 years ago

If a person wanted to calculate how much kinetic energy an object has, the equation they would use would be: Question 2 options:

nexus9112 [7]

Answer: $KE=\frac{1}{2}mv^{2}$

Explanation:

Kinetic Energy is the energy a particle, body or object possesses due to its movement and is mathematically defined as:

$KE=\frac{1}{2}mv^{2}$

Where:

$m$ is the mass of the body

$v$ is the velocity of the body

So, if we want to calculate the kinetic energy $KE$ of an object, we have to use the equation given above.

8 0

3 years ago