Which is greater, the mass of the compounds before a chemical reaction or the mass of the compounds after a chemical reaction?

What is apparent magnitude and what can affect it?

Montano1993 [528]

Apparent magnitude means how bright a star APPEARS to us on Earth. It can be affected by ...

... how bright the star really is
... how far the star is from us
... how much gas and dust is between us
... how much of the star's total output is in visible light

8 0

3 years ago

Please help what is the definition ligthspeed

aev [14]

Light speed is the speed at which light can travel in a "vacuum" (space for example).

The speed of light is constant and is exactly: 299,792,458 meters per second

ONLY IN A VACUUM!!

The speed of light changes when it goes through different mediums (such as from space to Earth, light travels slower in Earth).

Good luck!

3 0

3 years ago

Air expands adiabatically in a piston–cylinder assembly from an initial state where p1 = 100 lbf/in.2, v1 = 3.704 ft3/lb, and T1

lutik1710 [3]

Answer:

Final temperature is equal to 1291.63°R

Explanation:

given,

p₁ = 100 lb f/in², v₁ = 3.704 ft³/lb, and T₁ = 1000 °R

p₂ = 30 lb f/in² n = 1.4

Δ u = 0.171(T₂ - T₁)

we know for poly tropic process

p vⁿ = constant

p₁ v₁ⁿ = p₂ v₂ⁿ

100 × 3.704¹°⁴ = 30 × v₂¹°⁴

v₂ = 8.753 ft³/lb

work done for poly tropic process

W = $\dfrac{p_1v_1-p_2v_2}{n-1}$

= $\dfrac{100\times 3.704-30\times 8.753}{1.4-1}$

= 269.525 lbf/in².ft³

W = $\dfrac{269.525}{5.40395}$ Btu/lb

= 49.87 Btu/lb

in the piston cylinder arrangement air is expanding acrobatically

Δ q = Δu + w

Δ u = - w

0.171(T₂ - T₁) = -49.87

0.171(T₁ - T₂) = -49.87

0.171 T₂ = 0.171 × 1000 + 49.87

T₂ = 1291.63 °R

Final temperature is equal to 1291.63°R

5 0

3 years ago

An old clock has a spring that must be wound to make the clock hands move. Which statement describes the energy of the spring an

kondaur [170]

Answer:

D

Explanation:

When the spring is wound, then it gathers potential energy in the form of tension energy. As it slowly unwinds, the potential energy is converted to kinetic energy of the hands' movements of the clock. This energy is channeled through the use of cogs/gears in the clock.

7 0

3 years ago

Read 2 more answers

A comet is in an elliptical orbit around the Sun. Its closest approach to the Sun is a distance of 4.8 1010 m (inside the orbit

creativ13 [48]

Answer:

Explanation:

From the given information:

Distance $d_i = 4.8 \times 10^{10} \ m$

Speed of the comet $V_i = 9.1 \times 10^{4} \ m/s$

At distance $d_2 = 6 \times 10^{12} \ m$

where;

mass of the sun = $1.98 \times 10^{30}$

$G = 6.67 \times 10^{-11}$

To find the speed $V_f$ :

Using the formula:

$E_f = E_i + W \\ \\ where; \ \ W = 0 \ \ \text{since work done by surrounding is zero (0)}$

$E_f = E_i + 0 \\ \\ K_f + U_f = K_i + U_i \\ \\ = \dfrac{1}{2}mV_f^2 + \dfrac{-GMm}{d^2} = \dfrac{1}{2}mV_i^2+ \dfrac{-GMm}{d_i} \\ \\ V_f = \sqrt{V_i^2 + 2 GM \Big [ \dfrac{1}{d_2}- \dfrac{1}{d_i}\Big ]}$

$V_f = \sqrt{(9.1 \times 10^{4})^2 + 2 (6.67\times 10^{-11}) *(1.98 * 10^{30} ) \Big [ \dfrac{1}{6*10^{12}}- \dfrac{1}{4.8*10^{10}}\Big ]}$

$\mathbf{V_f =53.125 \times 10^4 \ m/s}$

3 0

3 years ago