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3 years ago

Difinition of gravity

Physics

2 answers:

erastovalidia [21]3 years ago

6 0

Answer:

it's all around you and it can't be destroyed

kiruha [24]3 years ago

3 0

Answer: The force that attracts a body toward the center of the earth, or toward any other physical body having mass.

Explanation:

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A ball rolls down the hill which has a vertical height of 15 m. Ignoring friction what would be the gravitational potential ener

trasher [3.6K]

a) Potential energy: 147 m [J]

The gravitational potential energy of an object is given by

$U=mgh$

where

m is its mass

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

h is the height of the object above the ground

In this problem,

h = 15 m

We call 'm' the mass of the ball, since we don't know it

So, the potential energy of the ball at the top of the hill is

$U=(m)(9.8)(15)=147 m$ (J)

b) Velocity of the ball at the bottom of the hill: 17.1 m/s

According to the law of conservation of energy, in absence of friction all the potential energy of the ball is converted into kinetic energy as the ball reaches the bottom of the hill. Therefore we can write:

$U=K=\frac{1}{2}mv^2$

where

v is the final velocity of the ball

We know from part a) that

U = 147 m

Substituting into the equation above,

$147 m = \frac{1}{2}mv^2$

And re-arranging for v, we find the velocity:

$v=\sqrt{2\cdot 147}=17.1 m/s$

5 0

3 years ago

I will mark as the brainliest answer<br><br>plz 8,9,10

blagie [28]

Answer:

8. acceleration = $\dfrac{d(velocity)}{d(time)}$ = 1 unit .

9. acceleration = $\dfrac{d(velocity)}{d(time)}$ = -1 unit.

10. acceleration = $\dfrac{d(velocity)}{d(time)}$ = 0 units.

Explanation:

8. i) acceleration = velocity / time

ii) In this figure velocity = time

iii) therefore acceleration = $\dfrac{d(velocity)}{d(time)}$ = 1 unit .

9. i) acceleration = velocity / time

ii) In this figure 4 = m + 5, therefore m = -1

therefore velocity = (-0.5 $\times$ time) + 5

iii) therefore acceleration = $\dfrac{d(velocity)}{d(time)}$ = -1 units.

10.) velocity is constant at 2

therefore acceleration = $\dfrac{d(velocity)}{d(time)}$ = 0 units

5 0

3 years ago

Please help on this one? The mass on the spring in this diagram is in harmonic motion between x = -5cm and x=5cm

shutvik [7]

c ... max speed zero accel

8 0

3 years ago

A guitarist finds that the pitch of one of her strings is slightly flat—the frequency is a bit too low. Should she increase or d

Yuri [45]

Answer:

The guitarist should increase the tension of the string.

Explanation:

The frequency of a vibrating string is determined by fn=(n/(2L))√T/μ. So if the tension in the string increased, the rate at which it vibrates (the frequency) will also increase.

Therefore it is advisable that she increase the tension of the string.

I hope it helps, please give brainliest if it does

6 0

3 years ago

Estimate the number of times the earth will rotate on its axis during a human’s lifetime

Fudgin [204]

Here we have to calculate the number of rotations made by earth around its own axis in the entire life time of a human being.

The average human life is 50 years .

Each year is 365.5 days

Hence $50 years =50 *365.5 days$

=18,275 days

The earth rotates around its own axis in 23 hours 56 minutes and 4 second which is approximately equal to 24 hours or one days.

Hence one rotation takes one days.

⇒18,275 days =18,275 rotations

Hence the total number of rotations made by earth around its own axis in the life time of a average human life time will be 18,275 times

7 0

3 years ago