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3 years ago

What speed is a car going if it takes 2 hours to go 80 miles?

2 answers:

8 0

Okay. If a car takes 2 hours to go 80 miles, the car is going 40 miles an hour. All you have to do is 80/2 in order to get your answer, because you do distance divided by time to find the speed.

user100 [1]3 years ago

4 0

The car would be moving at 40 miles per hour.

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Approximate the Sun as a uniform sphere of radius 6.96 X 108 m, rotating about its central axis with a period of 25.4 days. Supp

In-s [12.5K]

Answer:

T = 184 seconds

Explanation:

First in order to solve this, we need to know which is the expression to calculate the period. This is an exercise of angular velocity, so:

T = 2π/w

Where w: angular speed (in rad/s)

So, let's calculate first the innitial angular speed:

w = 2π/T

Converting days to seconds:

25.4 days * 24 h/day * 3600 s/h = 2,194,560 s

Then the angular speed:

w = 2π / 2,194,560 = 2.863x10^-6 rad/s

Now, the innitial angular momentum is:

I = (2/5)Mr² replacing data:

I = 2/5* (6.96x10^8)² * M = 1.94x10^17m² * M

so the initial angular momentum would be:

L = Iω = 2.863x10^-6 * 1.94x10^17 M

L = 5.55x10^11 m²/s * M = final angular momentum

Now the final I = 2/5Mr²

Final I = 2/5 * (6.37x10^6)² * M = 1.62x10^13m² * M

Then 5.55x10^11m²/s * M = 1.62x10^13m² * M * ω → M cancels

ω = 3.42x10^-2 rad/s

Then the new period

T = 2π/ω = 2*3.14 / 3.42x10^-2

T = 184 seconds

8 0

3 years ago

What is the name of the force that is a combination of all forces that act on an object?

jarptica [38.1K]

Answer:

If the combination of all the forces acting on an object sums upto be zero, then the net force is known as balanced force.

If the combination of all the forces acting on an object is non-zero, then the net force is said to be unbalanced force. The unbalanced force causes the object change the state of rest or motion.

6 0

3 years ago

Suppose a straight 1.00-mm-diameter copper wire could just "float" horizontally in air because of the force due to the Earth’s m

insens350 [35]

To solve this problem it is necessary to apply the concepts related to the Force since Newton's second law, as well as the concept of Electromagnetic Force. The relationship of the two equations will allow us to find the magnetic field through the geometric relations of density and volume.

$F_{mag}= BIL$

Where,

B = Magnetic Field

I = Current

L = Length

Note: $F_{mag}$ is a direct adaptation of the vector relation $F=q \times V \times B$

From Newton's second law we know that the relation of Strength and weight is determined as

$F_g = mg$

Where,

m = Mass

g = Gravitational Acceleration

For there to be balance the two forces must be equal therefore

$F_{mag} = F_g$

$BIL = mg$

Our values are given as,

Diameter $(d) = 1.0mm = 1*10^{-3}m$

Radius $(r) = \frac{d}{2} = \frac{1*10^{-3}}{2} = 0.5*10^{-3}m$

Magnetic Field $(B) = 5.0*10^{-5} T$

From the relationship of density another way of expressing mass would be

$\rho = \frac{m}{V} \rightarrow m = \rho V$

At the same time the volume ratio for a cylinder (the shape of the wire) would be

$V = \pi r^2 L \rightarrow L =Length, r= Radius$

Replacing this two expression at our first equation we have that:

$BIL = mg$

$BIL = ( \rho V)g$

$BIL = ( \rho \pi r^2 L)g$

Re-arrange to find I

$I = \frac{( \rho \pi r^2 L)g}{BL}$

$I = \frac{( \rho \pi r^2 )g}{B}$

We have for definition that the Density of copper is $8.9*10^3 Kg/m^3$ , gravity acceleration is $9.8m/s^2$ and the values of magnetic field (B) and the radius were previously given, then:

$I = \frac{( (8.9*10^3 ) \pi (0.5*10^{-3})^2 )(9.8)}{5.0*10^{-5}}$

$I = 1370.05A$

The current is too high to be transported which would make the case not feasible.

8 0

3 years ago

What is the name for the layer of cells at the back of the eye that contains photoreceptors?

Alona [7]

B.) The retina is the layer containing the light sensing nerve cells (rods and cones)

The lens helps the eye focus light on the retina, the cornea is the outer transparent structure that covers the iris and helps the eye focus, and the pupil is the opening through which light enters the eye.

4 0

3 years ago

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Calcium has a charge of +2. The chart lists the charges of different ions.

dexar [7]

The possible resulting chemical formulas for an ionic compound with calcium given the respective charges of the ions are: CaO, CaMg, or CaF₂ and CaO, CaF₂, or CaCl₂. This is because when dealing with these compounds, you simply need to interchange the oxidation state of the two elements and place as the subscript of the element. For instance, when we have Ca²⁺ and F⁻, the result is CaF₂. However, when the oxidation states of the two compounds are equal, the subscript is 1. That is, for Ca²⁺ and Mg²⁻, the result is CaMg. And for Ca²⁺ and Cl⁻, the result is CaCl₂.

3 0

3 years ago

Read 2 more answers