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3 years ago

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An object with a mass of 70 kilograms is supported at a height of 8 meters above the ground, what's the potential energy of the

object with respect to the ground?

1 answer:

Olegator [25]3 years ago

6 0

Answer:

5488 Joules

Explanation:

Use the formula for the potential energy:

$E_p = mgh = 70kg\cdot 9.8\frac{m}{s^2}\cdot 8m = 5488 J$

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The terminal velocity is not dependent on which one of the following properties? the drag coefficient 1 the force of gravity 2 c

ahrayia [7]

<h2>Answer: the falling time</h2>

Explanation:

When a body or object falls, basically two forces act on it:

1. The force of air friction, also called<em> </em><u><em>"drag force"</em></u> $D$ :

$D={C}_{d}\frac{\rho V^{2} }{2}A$ (1)

Where:

$C_ {d}$ is the drag coefficient

$\rho$ is the density of the fluid (air for example)

$V$ is the velocity

$A$ is the transversal area of the object

So, this force is proportional to the transversal area of the falling element and to the square of the velocity.

2. Its <u>weight </u>due to the gravity force $W$ :

$W=m.g$

(2)

Where:

$m$ is the mass of the object

$g$ is the acceleration due gravity

So, at the moment <u>when the drag force equals the gravity force, the object will have its terminal velocity:</u>

$D=W$ (3)

${C}_{d}\frac{\rho V^{2} }{2}A=m.g$ (4)

$V=\sqrt{\frac{2m.g}{\rho A{C}_{d}}}$ (5) This is the terminal velocity

As we can see, there is no "falling time" in this equation.

Therefore, the terminal velocity is not dependent on the falling time.

6 0

3 years ago

An emf source of 6.0V is connected to a purely resistive lamp and a current of 2.0 amperes flows. All the wires are resistance-f

IgorC [24]

Resistance = (voltage) / (current)

Resistance = (6.0 v) / (2.0 A)

Resistance = 3.0 ohms

7 0

3 years ago

. A 13-g goldfinch has a speed of 8.5 m/s. What is its kinetic energy?

lesya692 [45]

PLEASE PRESS THE “Thanks!” BUTTON! :)
13 g —> 0.013 kg
KE = 1/2(m)(v)^2
KE = 1/2(0.013)(8.5)^2
KE = 0.47 J

3 0

2 years ago

Two circus performers rehearse a trick in which a ball and a dart collide. Horatio stands on a platform 9.8 m above the ground a

xenn [34]

Answer:

Time = 0.55 s

Height = 8.3 m

Explanation:

The ball is dropped and therefore has an initial velocity of 0. Its acceleration, g, is directed downward in the same direction as its displacement, $h_b$ .

The dart is thrown up in which case acceleration, g, acts downward in an opposite direction to its displacement, $h_d$ . Both collide after travelling for a time period, t. Let the height of the dart from the ground at collision be $h_d$ and the distance travelled by the ball measured from the top be $h_b$ .

It follows that $h_d+h_b=9.8$ .

Applying the equation of motion to each body (h = v_0t + 0.5at^2),

Ball:

$h_b=0\times t + 0.5\times 9.8t^2$ (since $v_{b0} =0$ .)

$h_b=4.9t^2$

Dart:

$h_d=17.8\times t - 0.5\times9.8t^2$ (the acceleration is opposite to the displacement, hence the negative sign)

$h_d=17.8\times t - 4.9t^2$

But

$h_b+h_d =9.8$

$17.8\times t - 4.9t^2+4.9t^2 =9.8$

$17.8\times t = 9.8$

$t = 0.55$

The height of the collision is the height of the dart above the ground, $h_d$ .

$h_d=17.8\times t - 4.9t^2$

$h_d=17.8\times 0.55 - 4.9\times(0.55)^2$

$h_d=9.79 - 1.48225$

$h_d=8.3$

8 0

3 years ago

Where is UTC the local time?

Dmitrij [34]

UTC is generally adopted as the local time at Prime Meridian (PM).

<h3>What is UTC?</h3>

UTC is an abbreviation for Coordinated Universal Time and it can be defined as a local time standard by which all clocks, time and time zones are regulated around the world.

This ultimately implies that, Coordinated Universal Time (UTC) is generally adopted as the local time at Prime Meridian (PM) because it nominally reflects mean solar time.

Read more on UTC here: brainly.com/question/14333785

#SPJ12

5 0

2 years ago