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anastassius [24]

3 years ago

10

Select the correct answer. A sample of physical evidence was heated with dry cupric oxide. The issuing gas turned lime water mil

ky. Which element does the physical evidence contain? A. oxygen B. hydrogen C. carbon D. bromine E. chlorine

1 answer:

Elan Coil [88]3 years ago

4 0

Answer: C - carbon

Explanation:

Carbon dioxide (CO2) turns lime water milky due to the formation of insoluble calcium carbonate, CaCO3. Sulphur dioxide (SO2) also does the same, but slowly, as it reacts with calcium hydroxide to form insoluble calcium sulphite.

The physical evidence contain carbon elements

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A person exerts a 19-N force on a cart attached to a spring and holds the cart steady. The cart is displaced 0.060 m from its eq

Mariana [72]

To solve this problem, apply the concepts related to Hooke's law. From there we will find the spring constant. Subsequently, applying Energy balance, which includes gravitational potential energy, elastic potential energy and kinetic energy, we will bury the system's energy. Finally, using the displacement expression for the simple harmonic movement, we will find the expression that describes the system.

PART A) The expression for the spring force is

$F=kx$

Here,

k = Spring constant

x = Displacement

Rearranging to find the spring constant we have that

$k = \frac{F}{x}$

$k = \frac{19}{0.06}$

$k = 316.66N/m \approx 320N/m$

PART B ) The gravitational potential energy acts on the spring holds the cart is zero. Since cart is placed in the equilibrium position. The kinetic energy of the cart is zero. Therefore the expression for the total energy is,

$E = (PE)_g+(PE)_{spring}+KE$

$E = 0+\frac{1}{2} kx^2+0$

$E = \frac{1}{2} (316.66N/m)(0.06)^2$

$E = 0.569J \approx 0.57J$

PART C) The expression for the angular frequency is

$\omega = 2\pi f$

$\omega = 2\pi (1Hz)$

$\omega = 2\pi rad/s$

The equation for the motion of the cart is

$x(t)= Acos(\omega t)$

Replacing,

$x(t) = 0.06 cos (2\pi t)$

5 0

3 years ago

Although there are no glaciers in Florida , how have glaciers affected Florida?

Ksju [112]

They did not affect Florida- never came that far South.

5 0

3 years ago

A small block of mass M = 0.10 kg is released from rest at point 1 at a height H = 1.8 m above the bottom of a track, as shown i

Ede4ka [16]

Answer:

D

Explanation:

A) is not correct, because the gravitation potential energy will depend on the height the block is located at. It will be calculated with the formula:

U=mgh.

If we take the ground as a zero height reference, then on point 2 the potential energy will be:

$U_{2} = 0.10kg(9.81 m/s^{2})(0.6m)$

$U_{2}=0.59 J$

While on point 3, the potential energy will be greater.

$U_{3}=0.10kg(9.81 m/s^{2})(1.2m)$

$U_{3}=1.18 J$

B) is not the right answer because the kinetic energy will vary with the height the block is located at in the fact that the energy is conserved (this is if we don't take friction into account or air resistance) so in this case:

$U_{2}+K_{2}= U_{3}+K_{3}$

We already know the potential energy at point 2. We can calculate the kinetic energy at point 3 like this:

$K_{3} =\frac{1}{2}mv_{3}^{2}$

$K_{3} =\frac{1}{2}(0.10kg)(2.5 m/s)^{2}$

$K_{3} =0.31 J$

So the kinetic energy at point 2 is given by the equation:

$K_{2} =U_{3}-U_{2}+K_{3}$

so:

$K_{2} = (1.18J)-(0.59J)+0.31J$

$K_{2} =0.9J$

As you may see the kinetic energy at point 2 is greater than the kinetic energy at point 3.

C) Is not correct because according to the first law of thermodinamics, energy is not lost, only transformed. So, since we are not taking into account friction or any other kind of loss, then we can say that the amount of mechanical energy at point 1 is exactly the same as the mechanical energy at point 3.

D) Because of what we talked about on part C, this will be the true situation, because the mechanical energy of the block will be the same no matter theh point you measure it at.

7 0

3 years ago

Your fitness tracker tells you that you have delivered 124 kJ of work during your workout. The tracker also shows that you have

REY [17]

To solve this problem, we must basically count the total energy lost converting all the values given in the international system.

The energy loss is given by both 124KJ and 124food heats.

Since the energy conversion we know that 1 food calories is equal to 4,184J. So:

$124 calories (\frac{4.184J}{1 calories}) = 518.816J = 0.518816kJ$

Therefore the total energy lost will be

$E_{lost} = 124 KJ + 0.518816 KJ$

$E_{lost} = 124.518KJ$

Therefore the total energy lost to the surroindings in form of heat is 124.518kJ

3 0

3 years ago

A wave that can travel only through what is a mechanical wave

WINSTONCH [101]

The answer is matter

6 0

3 years ago