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Veseljchak [2.6K]

3 years ago

9

The unit for energy is the joule (j). If the energy content of an object is 1,000 J, but then later is found to be 900 J, what i

s the most logical
reason to explain what happened to 100J of its energy?

1 answer:

Dennis_Churaev [7]3 years ago

5 0

Answer: the object transferred some of its energy to its surroundings.

Explanation:

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Which ONE of the following pairs of physical quantities consists of one scalar and one vector quantity?

lyudmila [28]

Answer:

speed and acceleration

Explanation:

speed is a scalar quantity

acceleration is a vector quantity

7 0

2 years ago

What is the value of the composite constant (Gme,/r2e) to be multiplied by the mass of the object mo, in equation below:

Sedbober [7]

To solve this problem we will apply the definitions given in Newtonian theory about the Force of gravity, and the Force caused by weight. Both will be defined below, and in equal equilibrium condition to clear the variable concerning acceleration due to gravity. Finally, with the values provided in the statement, it will be replaced.

The equation for the gravitational force between the Earth and the object on the surface of the Earth is

$F_g = \frac{Gm_em_o}{r^2_e}$

Where,

G = Universal gravitational constant

$m_e$ = Mass of Earth

$r_e$ = Distance between object and center of earth

$m_o$ = Mass of Object

The equation for the gravitational pulling force on the object due to gravitational acceleration is

$F_g = m_o g$

Equation the two expression we have

$m_o g = \frac{Gm_em_o}{r_e^2}$

$g = \frac{Gm_e}{r_e^2}$

This the acceleration due to gravity which is composite constant.

Replacing with our values we have then

$g = \frac{(6.67*10^{-11}N\cdot m^2/kg^2)(5.98*10^{24}kg)}{6378km(\frac{10^3m}{1km})^2}$

$g = 9.8m/s^2$

The value of composite constant is $9.8m/s^2$ . Here, the composite constant is nothing but the acceleration due to gravity which is constant always.

8 0

3 years ago

What process is a method of heat transfer but does NOT contribute significantly to heating the surface or atmosphere of the eart

klasskru [66]

Answer:

conduction

Explanation:

Conduction is a method of heat transfer, where two objects exchange heat by touching, but does not contribute to moving heat through earth's atmosphere, because the atmosphere is so sparse it does not transmit heat through conduction effectively. Insulation is not a method of heat transfer.

7 0

3 years ago

Hardness is indirectly related to: specific gravity surface roughness strength of chemical bonds weight

Zepler [3.9K]

The strength of chemical bonds would be the best answer to this question. Hardness is indirectly related to the strength of chemical bonds. Hardness is the resistance from the destruction of an object itself from a material. Hardness does not need to strength of chemical bonds in order to have this resistance.

5 0

3 years ago

Read 2 more answers

A stone is dropped from the upper observation deck of a tower, 250 m above the ground. (Assume g = 9.8 m/s2.) (a) Find the dista

Vitek1552 [10]

(a) $y(t)=250 - 4.9 t^2$

For an object in free-fall, the vertical position at time t is given by:

$y(t) = h + ut - \frac{1}{2}gt^2$

where

h is the initial vertical position

u is the initial vertical velocity

g = 9.8 m/s^2 is the acceleration of gravity

t is the time

In this problem,

h = 250 m

u = 0 (the stone starts from rest)

So, the vertical position of the stone is given by

$y(t) = 250 - \frac{1}{2}(9.8) t^2 = 250 - 4.9 t^2$

(b) 7.14 s

The time it takes for the stone to reach the ground is the time t at which the vertical position of the stone becomes zero:

y(t) = 0

Which means

$y(t) = h - \frac{1}{2}gt^2=0$

So for the stone in the problem, we have

$250 - 4.9 t^2 = 0$

Solving for t, we find:

$t=\sqrt{\frac{250}{4.9}}=7.14 s$

(c) -70.0 m/s (downward)

The velocity of an object in free fall is given by the equation

$v(t) = u - gt$

where

u is the initial velocity

g = 9.8 m/s^2 is the acceleration of gravity

t is the time

Here we have

u = 0

So if we substitute t = 7.14 s, we find the velocity of the stone at the time it reaches the ground:

$v=0-(9.8 m/s^2)(7.14 s)=-70.0 m/s$

The negative sign means the direction of the velocity is downward.

(d) 6.94 s

In this situation, the stone is thrown downward with an initial speed of 2 m/s, so its initial velocity is

u = -2 m/s

So the equation of the vertical position of the stone in this case is

$y(t) = h + ut - \frac{1}{2}gt^2=250 - 2t - 4.9 t^2$

By solving the equation, we find the time t at which the stone reaches the ground.

We find two solutions:

t = -7.35 s

t = 6.94 s

The first solution is negative, so it has no physical meaning, therefore we discard it. So, the time it takes for the stone to reach the ground is:

t = 6.94 s

6 0

3 years ago