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3 years ago

A net downward force of 20 N causes a book to fall towards the ground at m/s2. What is the book’s mass? Consider air resistance

Physics

1 answer:

stira [4]3 years ago

4 0

If we have to figure air resistance into it, then we don't have enough information to find an answer.

If the air around it is going to have an effect on how it falls, then it'll depend on the thickness of the book, the shape of the book, whether it's a hard-cover or soft-cover, how far the covers stick out past the pages, how smooth or rough the covers are, how bumpy the binding it. and what position you hold it in before you let it go.

(THAT's why we always ignore air resistance, especially when the question is actually about gravity anyway.)

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In order to place a satellite into orbit, it requires enough fuel to supply the necessary mechanical energy. Into what types of

nexus9112 [7]

When a satellite is revolving into the orbit around a planet then we can say

net centripetal force on the satellite is due to gravitational attraction force of the planet, so we will have

$F_g = F_c$

$\frac{GM_pM_s}{r^2} = \frac{M_s v^2}{r}$

now we can say that kinetic energy of satellite is given as

$KE = \frac{1}{2}M_s v^2$

$KE = \frac{GM_sM_p}{2r}$

also we know that since satellite is in gravitational field of the planet so here it must have some gravitational potential energy in it

so we will have

$U = -\frac{GM_sM_p}{r}$

so we can say that energy from the fuel is converted into kinetic energy and gravitational potential energy of the satellite

6 0

3 years ago

Which equation can be used to solve for acceleration? <br><br>

antoniya [11.8K]

A = d/t
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3 0

4 years ago

Read 2 more answers

A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 3.00 m/s, and

Leya [2.2K]

Answer:

A) 0.9844 s

B) x2 = 0.4587 m

C) v = 6.657 m/s

Explanation:

We are given;

Height of take off point above pool; x1 = 1.8 m

Initial take off velocity; u = 3 m/s

Final velocity at highest point before free fall; v = 0 m/s

B) To find the highest point above the board her feet reaches means the distance from take off to the top of the motion just before free fall.

Thus, we will be using equation of motion and we have;

v² = u² + 2gs

Now, let s = x2 which will be the distance between take off and the top before free fall.

So;

v² = u² + 2g(x2)

Now,since the motion is against gravity, g will be negative.

Thus;

v² = u² + 2(-9.81)(x2)

Plugging in the relevant values to give;

0² = 3² - (19.62x2)

19.62(x2) = 9

x2 = 9/19.62

x2 = 0.4587 m

A) We want to find how long her feet is in air.. It means we want to find out the time to get to a distance of x1 and also the time to achieve the distance (x1 + x2) on free-fall.

Thus, using equation of motion;

v = u + gt

Again, g = -9.81

Thus;

0 = 3 - 9.81t1

9.81t1 = 3

t1 = 3/9.81

t1 = 0.3058 s

Now, for the time taken to achieve the distance (x1 + x2) on free-fall, we will use the formula;

s = ut + ½gt²

Where s = (x1 + x2) = 1.8 + 0.4587 = 2.2587 m

And now, u = 0 m/s because the start of the free fall is from maximum height with velocity of 0 m/s. Again, g = - 9.81 m/s²

Thus;

2.2587 = 0 - ½(-9.81)(t2)²

2.2587 = 4.905(t2)²

(t2)² = 2.2587/4.905

(t2)² = 0.4605

t2 = √0.4605

t2 = 0.6786 s

Thus, total time of feet in air = t1 + t2 = 0.3058 + 0.6786 = 0.9844 s

C) Velocity when feet hit the water would be given by;

v = u + gt

Where u = 0 m/s and t = t2 = 0.6786

Since it's in direction of gravity, g = 9.81 m/s

v = 0 + (0.6786 × 9.81)

v = 6.657 m/s

4 0

4 years ago

If your body is dehydrated, the control center in the brain will stimulate the release of a hormone which causes the reabsorptio

Yanka [14]

Answer:

It is an example of negative feedback mechanism

Explanation:

Negative feedback mechanism is the process by which the output of a system, process or mechanism is fed back into the input in order to reduce the error in the system.

In the system described in this question, the reabsorption of water is the output, a feedback signal is sent to the control center, which is the input in order to control the release of the hormone responsible for reabsorption of water into the blood.

7 0

3 years ago

light of a certain frequency has a wavelength of 438 nm in water.What is the wavelength of this light in benzene

sveticcg [70]

Answer:

388.97 nm

Explanation:

The computation of the wavelength of this light in benzene is shown below:

As we know that

n (water) = 1.333

n (benzene) = 1.501

$\lambda (water) \times n(water) = \lambda (benzene) \times n(benzene)$

And, the wavelength of water is 438 nm

$\lambda (benzene) = \lambda (water) [\frac{n(water)}{n(benzene}]$

Now placing these values to the above formula

So,

$= 438 \times \frac{1.333}{1.501}$

= 388.97 nm

We simply applied the above formula so that we can easily determine the wavelength of this light in benzene could come

5 0

3 years ago