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3 years ago

"The gravity of the Sun causes the planets to move in a circular path."

1 answer:

3 0

You're thinking of Kepler's first law of planetary motion, but that's not
what it says.

First of all, Kepler didn't say anything about gravity. He only described
the orbits. And he said that the orbit of each planet is an ellipse, with the
sun at one focus.

If by some chance you're thinking of Newton ... he showed that if his formula for
gravity is correct, then the orbit of a planet must be an ellipse. But Newton's law
of gravity is not one of his so-called "three laws of motion".

You might be interested in

A heavy boy and a lightweight girl are balanced on a massless seesaw. The boy moves backward, increasing his distance from the p

slava [35]

Answer:

b. The side the boy is sitting on will tilt downward

Explanation:

Initially, the seesaw is balanced because the torque exerted by the boy is equal to the torque exerted by the girl:

$\tau_b = \tau_g\\W_b d_b = W_g d_g$

where

Wb is the weight of the boy

db is the distance of the boy from the pivot

Wg is the weight of the girl

dg is the distance of the girl from the pivot

When the boy moves backward, the distance of the boy from the pivot ( $(d_b)$ increases, therefore the torques are no longer balanced: the torque exerted by the boy will be larger, and therefore the side of the boy will tilt downward.

5 0

3 years ago

The speed of sound in ice, water, and steam is shown. What best explains the speed of sound in different states of matter?

Marina86 [1]

The speed of sound is greater in ice (4000 m/s), then in water (1500 m/s), then in air (340 m/s). The explanation for this is the differente state of the matter in the three cases.

In fact, sound waves travel faster in solids (like ice), then in liquids (like water), then in gases (like air). This is because the speed of the sound wave depends on the density of the medium: the greater the density, the faster the sound wave. This can be easily understood by thinking at how a sound wave propagates: a sound wave is a vibration of molecules, which is transmitted throughout the medium by collision of the molecules. Therefore, the smaller the spacing between the molecules (such as in solids), the more efficient is the propagation, and so the sound wave is faster. On the contrary, there is a large spacing between molecules in gases (such as in the air), so there are less collisions between the molecules and so the wave is not transmitted efficiently, and so it has less velocity.

5 0

3 years ago

Read 2 more answers

What is the amount of thermal energy needed to make 5 kg of ice at - 10 °C to

agasfer [191]

Answer:

The amount of thermal energy needed is 15167500 joules.

Explanation:

By First Law of Thermodynamics, we see that amount of thermal energy ( $Q$ ), in joules, is equal to the change in internal energy. From statement we understand that change in internal energy consisting in two latent components ( $U_{l,ice}$ , $U_{l,steam}$ ), in joules, and two sensible component ( $U_{s,w}$ ), in joules, that is:

$Q = U_{l,ice} + U_{s, w} + U_{s,ice} + U_{l,steam}$ (1)

By definitions of Sensible and Latent Heat, we expanded the formula:

$Q = m\cdot (h_{f,w}+h_{v,w}+c_{ice}\cdot \Delta T_{ice}+c_{w}\cdot \Delta T_{w})$ (2)

Where:

$m$ - Mass, in kilograms.

$h_{f,w}$ - Latent heat of fussion of water, in joules per kilogram.

$h_{v,w}$ - Latent heat of vaporization of water, in joules per kilogram.

$c_{ice}$ - Specific heat of ice, in joules per kilogram per degree Celsius.

$c_{w}$ - Specific heat of water, in joules per kilogram per degree Celsius.

$\Delta T_{ice}$ - Change in temperature of ice, measured in degrees Celsius.

$\Delta T_{w}$ - Change in temperature of water, measured in degrees Celsius.

If we know that $m = 5\,kg$ , $h_{f,w} = 3.34\times 10^{5}\,\frac{J}{kg}$ , $h_{v,w} = 2.26\times 10^{6}\,\frac{J}{kg}$ , $c_{ice} = 2.090\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}$ , $c_{w} = 4.186\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}$ , $\Delta T_{ice} = 10\,^{\circ}C$ and $\Delta T_{w} = 100\,^{\circ}C$ , then the amount of thermal energy is:

$Q = 15167500\,J$

The amount of thermal energy needed is 15167500 joules.

7 0

2 years ago

Two streams merge to form a river. One stream has a width of 8.4 m, depth of 3.5 m, and current speed of 2.2 m/s. The other stre

hoa [83]

Answer:

Explanation:

We shall solve this problem on the basis of pinciple that water is incompressible so volume of flow will be equal at every point .

rate of volume flow of one stream

= cross sectional area x velocity

= 8.4 x 3.5 x 2.2 = 64.68 m³ /s

rate of volume flow of other stream

= 6.6 x 3.6 x 2.7

= 64.15 m³ /s

rate of volume flow of rive , if d be its depth

= 11.2 x d x 2.8

= 31.36 d

volume flow of river = Total of volume flow rate of two streams

31.36 d = 64.15 + 64.68

31.36 d = 128.83

d = 4.10 m /s .

6 0

2 years ago

How do two objects at different temperatures attain thermal equilibrium?

Lady bird [3.3K]

Answer:

C.As the two objects touch, thermal energy flows as heat from the warmer block to the colder block until particles in both blocks move at the same rate and reach the same temperature.

Explanation:

Heat is the transfer of thermal energy from an object at higher temperature to an object at colder temperature.

The temperature of an object is a measure of how fast the particles in the object move: the higher its temperature, the faster the particles move, the higher the average kinetic energy of the particles in the object. As a result, the particles of the object at higher temperature tend to transfer more energy (called thermal energy) to the particles of the object at colder temperature by colliding with them: this process continues until the particles of the colder object reach the same average kinetic energy as the particles of the warmer object, and this means that the two objects have reached the same temperature.

3 0

3 years ago