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3 years ago

What is gravity???☺️

Physics

2 answers:

saveliy_v [14]3 years ago

4 0

A force that pulls objects downwards

AfilCa [17]3 years ago

3 0

Answer:

Gravity

Explanation:

its an invisible force that pulls objects

toward each other.

hope it helps

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When the starter motor on a car is engaged, there is a 290 A current in the wires between the battery and the motor. Suppose the

Tema [17]

Answer:

$33.6\times10^{-4}}\text{ m}$ = 3.36 mm

Explanation:

From Ohm's law,

$V = IR$ (Voltage = Current * Resistance)

$R = \dfrac{V}{I}$

The geometric definition of resistance is

$R = \rho\dfrac{l}{A}$

where $\rho$ is the resistivity of the material, $l$ and $A$ are the length and cross-sectional area, respectively.

$A = \rho\dfrac{l}{R}$

$A = \rho\dfrac{l\timesI}{V}$

Since the wire is assumed to have a circular cross-section, its area is given by

$A = \pi\dfrac{d^2}{4}$ where $d$ is the diameter.

$\pi\dfrac{d^2}{4} = \rho\dfrac{l\timesI}{V}$

$d = \sqrt{\dfrac{4\rho l I}{\pi\times V}}$

Resistivity of copper = $1.68\times10^{-8}$ . With these and other given values,

$d = \sqrt{\dfrac{4\times1.68\times10^{-8}\times1.5\times290}{3.14\times 0.55}}$

$d = \sqrt{1128.43\times10^{-8}}$

$d = 33.6\times10^{-4} \text{ m}$

5 0

3 years ago

Out of all the mass and energy in the universe, ordinary matter (the stuff that makes up stars and gas, and all the things we in

MrMuchimi

Answer:

About 5 % of the universe is visible.

Estimates are that 68 % of the universe consists of "dark energy" and 27% of the universe consists of "dark matter". Currently 95 % of the universe is not currently visible to the scientists involved (cannot be explained by means that we know).

5 0

2 years ago

An empty rubber balloon has a mass of 12.5 g. The balloon is filled with helium at a density of 0.181 kg/m3. At this density the

Eduardwww [97]

Answer: 1.14 N

Explanation :

As any body submerged in a fluid, it receives an upward force equal to the weight of the fluid removed by the body, which can be expressed as follows:

Fb = δair . Vb . g = 1.29 kg/m3 . 4/3 π (0.294)3 m3. 9.8 m/s2

Fb = 1.34 N

In the downward direction, we have 2 external forces acting upon the balloon: gravity and the tension in the line, which sum must be equal to the buoyant force, as the balloon is at rest.

We can get the gravity force as follows:

Fg = (mb +mhe) g

The mass of helium can be calculated as the product of the density of the helium times the volume of the balloon (assumed to be a perfect sphere), as follows:

MHe = δHe . 4/3 π (0.294)3 m3 = 0.019 kg

Fg = (0.012 kg + 0.019 kg) . 9.8 m/s2 = 0.2 N

Equating both sides of Newton´s 2nd Law in the vertical direction:

T + Fg = Fb

T = Fb – Fg = 1.34 N – 0.2 N = 1.14 N

6 0

3 years ago

Which feature of a heating curve indicates a change of state?

Andreas93 [3]

A "heating curve" is a graph that shows the temperature of the substance
against the amount of heat you put into it.

For most of the graph, as you'd expect, the temperature goes up as you
add heat, and it goes down as you take heat away. BUT ... While the
substance is changing state, its temperature doesn't change even though
you're putting heat in or taking heat out.

So that part of the graph is a horizontal line.

7 0

3 years ago

Read 2 more answers

an elevator mass of 7700 kg falls from a height of 32 m after a sudden failure in the hoisting cable. The mass is stopped by a s

valkas [14]

Answer:k=28.29 kN/m

Explanation:

Given

mass $m =7700 kg$