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2 years ago

A 2 kg stone moves with a speed of 1 m/s. A second 2 kg stone is moving twice as fast. Compare their kinetic energies.

Physics

2 answers:

alekssr [168]2 years ago

5 0

D
is the answer
Well it should be

patriot [66]2 years ago

3 0

Answer:

D is the answer

Explanation:

i did a test with this question on discovery education and i got it right

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Two cables of the same length are made of the same material, except that one cable has twice the diameter of the other cable. Wh

belka [17]

Answer: The same current flows through bth cables

Explanation:

Lets have a look to the next two equations

The Ohm´s V = I*R (1)

where:

V is voltage (potencial dfference) in volts

I is the electric current in ampers

R is the electric resistance

When a voltage is applied as the electrc load is not specified ( we have to assume is the same) the current will be the same

And in the other hand the resistance R =ρL/s

Where ρ is the resistivity of the conductor L the length and s square section of the conductor

If we assume that the smaller diameter cable is able to conduct the current then nothing happens. The point is that the capacity of conduction of current depend on the section of the cable (the area)

Tables exist where to find the capacity of each cable according to its diameter.

6 0

2 years ago

In ideal flow, a liquid of density 850 kg/m3 moves from a horizontal tube of radius 1.00 cm into a second horizontal tube of rad

Crank

Answer:

a) Q = π r₁ √ 2ΔP / rho [r₁² / r₂² -1] , b) Q = 3.4 10⁻² m³ / s , c) Q = 4.8 10⁻² m³ / s

Explanation:

We can solve this fluid problem with Bernoulli's equation.

P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂

With the two tubes they are at the same height y₁ = y₂

P₁-P₂ = ½ ρ (v₂² - v₁²)

The flow rate is given by

A₁ v₁ = A₂ v₂

v₂ = v₁ A₁ / A₂

We replace

ΔP = ½ ρ [(v₁ A₁ / A₂)² - v₁²]

ΔP = ½ ρ v₁² [(A₁ / A₂)² -1]

Let's clear the speed

v₁ = √ 2ΔP /ρ[(A₁ / A₂)² -1]

The expression for the flow is

Q = A v

Q = A₁ v₁

Q = A₁ √ 2ΔP / rho [(A₁ / A₂)² -1]

The areas are

A₁ = π r₁

A₂ = π r₂

We replace

Q = π r₁ √ 2ΔP / rho [r₁² / r₂² -1]

Let's calculate for the different pressures

r₁ = d₁ / 2 = 1.00 / 2

r₁ = 0.500 10⁻² m

r₂ = 0.250 10⁻² m

b) ΔP = 6.00 kPa = 6 10³ Pa

Q = π 0.5 10⁻² √(2 6.00 10³ / (850 (0.5² / 0.25² -1))

Q = 1.57 10⁻² √(12 10³/2550)

Q = 3.4 10⁻² m³ / s

c) ΔP = 12 10³ Pa

Q = 1.57 10⁻² √(2 12 10³ / (850 3)

Q = 4.8 10⁻² m³ / s

5 0

2 years ago

An object on a number line moved from x = 15 cm to x = 165 cm and then

olasank [31]

Answer:

v_avg = 2.9 cm/s

Explanation:

The average velocity of the object is the sum of the distance of all its trajectories divided the time:

$v_{avg}=\frac{x_{all}}{t}$

x_all is the total distance traveled by the object. In this case you have that the object traveled in the first trajectory 165cm-15cm = 150cm, and in the second one, 165cm - 25cm = 140cm

Then, x_all = 150cm + 140cm = 290cm

The average velocity is, for t = 100s

$v_{avg}=\frac{290cm}{100s}=2.9\frac{cm}{s}$

hence, the average velocity of the object in the total trajectory traveled is 2.9 cm/s

3 0

2 years ago

Read 2 more answers

A uniform cylindrical steel wire (density: 7.8 x 103 kg/m3), 58.0 cm long and 1.34 mm in diameter, is fixed at both ends. To wha

lbvjy [14]

Answer:

T= 354.65 N

Explanation:

Given that

ρ= 7800 kg/m³

L= 58 cm

d=1.34 mm

f= 311 Hz

T= Tension

Speed of wave ,V

V = f λ

V = f L

V= 311 x 0.58 m/s

V=180.38 m/s

Area of cross sectional

A= πr² mm²

A= 3.14 x 0.67² mm²

A=1.41 mm²

Mass = Density x Volume

$m=7800\times 1.41\times 10^{-6}\ kg/m$

m=0.0109 kg/m

Tension ,T

$T=m V^2$

T= 0.0109 x 180.38² N

T= 354.65 N

3 0

2 years ago

Grain is pored into a silo to be stored for later use. Due to the friction between pieces of grain as they rub against eachother

MariettaO [177]

Answer:

3.1×10⁻¹¹ N

Explanation:

Use Coulomb's law:

F = k q₁ q₂ / r²

F = (9×10⁹) (6.0×10⁻¹⁰) (2.3×10⁻¹⁵) / (0.02 m)²

F = 3.1×10⁻¹¹

6 0

2 years ago