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3 years ago

What do hydrogen and helium have in common?

1 answer:

4 0

Atomic disguise makes helium look like hydrogen. ... A helium atom consists of a nucleus containing two positively charged protons and two neutrons, encircled by two orbiting electrons which carry a negative charge. A hydrogen atom has just one proton and one electron

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A box slides down a frictionless plane inclined at an angle θ above the horizontal. The gravitational force on the box is direct

tamaranim1 [39]

Answer:

D) Vertically.

Explanation:

A free body diagram is used to represent all the forces acting in a body. forces like, the force of gravity as a result of the gravitational interaction between the object and the Earth (W), the frictional force opposite to the movement of the object ( $F_{r}$ ), the normal force due to the plane and the object (N) and the force applied to start the movement in a particular direction (F).

As is show in the free body diagram of the system, W, which is the weight of the body as a consequence of the gravitational force, is at an angle $\theta$ below the inclined plane. that angle between the plane and the x axis is the same that the one of the inclined plane with respect to the horizontal, Since its sides are perpendicular.

Notice how W goes always in the direction to the center of mass of Earth in a vertical path (For comparison see figure (a) and (b)).

4 0

3 years ago

The energy that generates wind comes from what source?

mamaluj [8]

The energy that generates wind on an individual basis originates with
one's habitual diet. On a world-wide basis, it comes from the sun.

6 0

3 years ago

Asteroid Ida was photographed by the Galileo spacecraft in 1993, and the photograph revealed that the asteroid has a small moon,

Nady [450]

Answer:

The orbital speed of Dactyl is $5.55m/s$

Explanation:

The orbital speed can be determined by the combination of the universal law of gravity and Newton's second law:

$F = G\frac{M \cdot m}{r^{2}}$ (1)

Where G is gravitational constant, M is the mass of the asteroid, m is the mass of the moon and r is the distance between them

In the other hand, Newton's second law can be defined as:

$F = ma$ (2)

Where m is the mass and a is the acceleration

Then, equation 2 can be replaced in equation 1

$m\cdot a = G\frac{M \cdot m}{r^{2}}$ (2)

However, a will be the centripetal acceleration since the moon Dactyl describe a circular motion around the asteroid

$a = \frac{v^{2}}{r}$ (3)

$m\frac{v^{2}}{r} = G\frac{M \cdot m}{r^{2}}$ (4)

Therefore, v can be isolated from equation 4:

$m \cdot v^{2} = G \frac{M \cdot m}{r^{2}}r$

$m \cdot v^{2} = G \frac{M \cdot m}{r}$

$v^{2} = G \frac{M \cdot m}{rm}$

$v^{2} = G \frac{M}{r}$

$v = \sqrt{\frac{G M}{r}}$ (5)

Finally, the orbital speed can be found from equation 5:

Notice, that it is necessary to express r in units of meters.

$r = 95km \cdot \frac{1000m}{1km}$ ⇒ $95000m$

$v = \sqrt{\frac{(6.672x10^{-11}N.m^{2}/kg^{2})(4.4x10^{16}kg)}{95000m}}$

$v = 5.55m/s$

Hence, the orbital speed of Dactyl is $5.55m/s$

3 0

3 years ago

The amplitude of a lightly damped oscillator decreases by 3.42% during each cycle. What percentage of the mechanical energy of t

frozen [14]

Answer:

The percentage of the mechanical energy of the oscillator lost in each cycle is 6.72%

Explanation:

Mechanical energy (Potential energy, PE) of the oscillator is calculated as;

PE = ¹/₂KA²

During the first oscillation;

PE₁ = ¹/₂KA₁²

During the second oscillation;

A₂ = A₁ - 0.0342A₁ = 0.9658A₁

PE₂ = ¹/₂KA₂²

PE₂ = ¹/₂K (0.9658A₁)²

PE₂ = (0.9658²)¹/₂KA₁²

PE₂ = (0.9328)¹/₂KA₁²

PE₂ = 0.9328PE₁

Percentage of the mechanical energy of the oscillator lost in each cycle;

$Change \ in \ percent= \frac{PE_2 - PE_1}{PE_1} \\\\Change \ in \ percent= \frac{0.9328PE_1 -PE_1}{PE_1} *100\\\\Change \ in \ percent= \frac{-0.0672PE_1}{PE_1}*100 \\\\Change \ in \ percent= -0.0672*100\\\\Change \ in \ percent= -6.72 \ \% \\\\Loss \ in \ percent= 6.72 \ \%$

Therefore, the percentage of the mechanical energy of the oscillator lost in each cycle is 6.72%

4 0

3 years ago

Speed has ____ magnitude and _____ direction ??

ArbitrLikvidat [17]

Speed has only magnitude and no direction.

6 0

3 years ago