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BlackZzzverrR [31]
2 years ago
8

If you are holding a book and you let go of it, why does it fall? Explain in terms of forces, potential energy, and kinetic ener

gy.
Physics
1 answer:
inessss [21]2 years ago
3 0

Answer:

Let the mass of the book be "m", acceleration due to gravity be "g", velocity be "v" and height be "h".

Now if we are holding a book at a certain height (h), <em><u>the potential energy will be maximum which is equal to mass× acceleration due to gravity× height (= mgh)</u>.</em>

(Remember: kinetic energy =0)

Now we consider that the book is dropped, in this case a force will act downward towards the centre of the earth, <em><u>Force= mass× acceleration due to gravity (F=mg)</u></em>. It is equal to the weight of the book.

While the book is falling, the potential energy stored in the book converts into kinetic energy and strikes the floor with <em><u>the maximum kinetic energy= (1/2)×mass×velocity² (=1/2mv²)</u>.</em>

(Remember: kinetic energy=0)

Due to this process the whole energy is conserved.

As the potential energy decreases kinetic energy increases.

You might be interested in
Two bricks are released at the same time from the same point ten feet above the ground. One of the bricks is falling straight do
natita [175]
Both bricks will hit the ground at the same time.

Falling vertically is always accelerating at 9.8 m/s² because of gravity.
Nothing that's happening horizontally has any effect on that.
The brick that happens to have some horizontal motion will 
probably hit the ground way over there, but that will still be
at the same TIME as this one.

This is a perfect place to remind you of the old unbelievable story,
which I'll bet you heard before:

If you fire a bullet horizontally from a gun, and at the exact same
moment you DROP another bullet out of your hand next to the gun,
the two bullets will hit the ground at the same time !  Even though
they'll be far apart.

Horizontal speed has no effect on vertical behavior.
7 0
2 years ago
A boat traveling across a river has a resultant velocity of 10 km/h and travels 34 degrees with respect to the shore. A) What is
vodka [1.7K]

Answer:

a) 1.55 m/s

b) 2.3 m/s

Explanation:

We know that the boat travels across the river, if we define the river as the x-axis, then the velocity of the boat is only on the y-axis.

Then we can write the velocity of the boat in still water as:

S = (0, B)

Now, when the boat is on the river, the velocity of the boat will be equal to the velocity of the boat in still water plus the velocity of the river.

The velocity of the river is:

v = (R, 0).

Then the velocity of the boat in that river is:

V' = (0, B) + (R, 0) = (R, B)

Now, we know that the velocity of the boat is 10km/h, and it travels at an angle of 34° with respect to the shore.

We can use the Pythagoreans theorem to write the components of this velocity as:

x-axis component = 10km/h*cos(34°) = 8.29 km/h

y-axis component = 10km/h*sin(34°) =  5.59 km/h

Then the velocity of the boat can be written in components as:

velocity = ( 8.29 km/h,  5.59 km/h)

And we knew that the velocity of the boat was written as  (R, B)

Then we must have:

R = 8.29 km/h

B = 5.59 km/h

a) The speed of the boat in m/s:

We know that the speed of the boat is 5.59 km/h.

First, we know that:

1km = 1000m, then:

5.59 km/h = 5.59*(1000m)h = 5,590 m/h

And we know that:

1h = 3600s

Then we can write:

5,590 m/h = 5,590 m/(3600s) = 1.55 m/s

b) The speed of the river in m/s:

We know that the speed of the river is 8.29 km/h

Using the same reasoning as above, we can do the change of units as follows:

8.29 km/h = 8.29 (1000m)/(3600s) = 2.3 m/s

6 0
2 years ago
•Would a moving fan have energy? Why or why not.
Pepsi [2]
Moving fan has rotational kinetic energy
Non moving fan has no energy since it is in rest
7 0
3 years ago
Heat can be transferred in several ways. Which of the following is an example of conduction? (DOK 2) A The sun is shining on a m
forsale [732]

Answer:

Explanation:

G yvyvybybybububunununu

8 0
3 years ago
Which example possesses mechanical potential energy?. A. a taut guitar string. B. an oscillating pendulum. C. a roller coaster r
Andrej [43]
<span>
The taut guitar string haspotencial energy which we can see in action.</span>  <span>· so option a is correct.</span>
6 0
2 years ago
Read 2 more answers
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