In what order were the following energy sources<br> discovered by humans

I would like help with this physics problem

Darina [25.2K]

(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.

Recall that

$v_f=v_i+at$

We have $v_f=-v_i$ , so that

$-2v_i=at\implies-2\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)=\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)t\implies t=8\,\mathrm s$

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.

(c) The ball's average velocity is 0. Average velocity is given by $\dfrac{v_i+v_f}2$ , and we know that $v_f=-v_i$ .

(d) The position of the ball $x_f$ at time $t$ is given by

$x_f=x_i+v_it+\dfrac12at^2$

Take the starting position to be the origin, $x_i=0$ . Then after 6 seconds,

$x_f=\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)(6\,\mathrm s)+\dfrac12\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)(6\,\mathrm s)^2=42\,\mathrm m$

so the ball is 42 m away from where it started.

We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

$x_f-x_i=\dfrac{v_i+v_f}2t\implies42\,\mathrm m=\dfrac{8\,\frac{\mathrm m}{\mathrm s}+v_f}2(6\,\mathrm s)\implies v_f=6\,\dfrac{\mathrm m}{\mathrm s}$

Since the velocity is positive, the ball is still moving up the incline.

8 0

3 years ago

Which of the following explains how electrical charges flow? From areas of high-potential to areas of low-potential From areas o

skad [1K]

From areas of high potential to low potential. That is, high voltage to low voltage.

8 0

3 years ago

Read 2 more answers

The motion of an orbiting satellite can be described by the same motion characteristic of any object in uniform circular motion.

densk [106]

The force exerted by Earth plays the role of centripetal force.

6 0

3 years ago

Which of the motion variables is the same in both thex and y axis?

Softa [21]

Answer:

Acceleration (b) not sure tho

Explanation:

7 0

3 years ago

Which metal would cause the greatest increase in the temperature of the water in the calorimeter: the one with the highest speci

masha68 [24]

<h3><u>Answer;</u></h3>

the one with the highest specific heat

<h3><u>Explanation;</u></h3>

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.
The specific heat of water is 1 calorie/gram °C or 4.186 joule/gram °C which is higher than any other common substance.
<em><u>A metal with the highest specific heat will cause the greatest increase in temperature of water in a calorimeter because the metal would hold more heat, and then transfer the greater quantity of heat to the water.</u></em>

4 0

4 years ago

In what order were the following energy sources discovered by humans