1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Viefleur [7K]
2 years ago
15

A gazelle is running at 17.46 m/s. He sees a lion and accelerates at -1.49 m/s/s,

Physics
2 answers:
natka813 [3]2 years ago
7 0
Answer=21.0211m/s

Explanation v=17.46/
Vsevolod [243]2 years ago
5 0

Answer:

V=21.0211m/s

Explanation:

Use V=vi+at

So, V=17.46m/s+(1.49m/s^{2})(2.39s)= 21.0211m/s

You might be interested in
HOW MANY PIES DOSE IT TAKE TO GET TO THE MOON
Schach [20]

i do not have an answer because it depends on the size and the distance lol

8 0
3 years ago
What type of heat transfer is used in a restaurant that uses ovens with fans inside?
Marina CMI [18]

convection


please mark brainliest any other problems or questions feel free to ask


5 0
3 years ago
Which is one<br> step that geologists use to find the epicenter of an earthquake?
Kisachek [45]

Answer:

triangulation

Explanation:

using your compass

5 0
3 years ago
Read 2 more answers
4) A satellite, mass m, is in circular orbit (radius r) around the earth, which has mass ME and radius Re. The value of r is lar
defon
<h2>Answers:</h2>

(a) The kinetic energy of a body is that energy it possesses due to its movement and is defined as:

K=\frac{1}{2}m{V}{2}     (1)

Where m is the mass of the body and V its velocity.

In this specific case of the satellite, its kinetic energy K_m taking into account its mass m is:

K_{m}=\frac{1}{2}m{V}^{2}     (2)

On the other hand, the velocity of a satellite describing a circular orbit is constant and defined by the following expression:

V=\sqrt{G\frac{ME}{r}}     (3)

Where G is the gravity constant, ME the mass of the Earth and r the radius of the orbit <u>(measured from the center of the Earth to the satellite). </u>

Now, if we substitute the value of V from equation (3) on equation (2), we will have the final expression of the kinetic energy of this satellite:

K_{m}=\frac{1}{2}m{\sqrt{G\frac{ME}{r}}}^{2}     (4)

Finally:

K_{m}=\frac{1}{2}Gm\frac{ME}{r}     (5)  >>>>This is the kinetic energy of the satellite

(b) According to Kepler’s 2nd Law applied in the case of a circular orbit, its Period T is defined as:

T=2\pi\sqrt{\frac{r^{3}}{\mu}}     (6)

Where \mu is a constant and is equal to GME. So, this equation in these terms is written as:

T=2\pi\sqrt{\frac{r^{3}}{GME}}     (7)

As we can see, <u>the Period of the orbit does not depend on the mass of the satellite </u>m, it depends on the mass of the greater body (the Earth in this case) ME, the radius of the orbit and the gravity constant.

(c) The gravitational force described by the law of gravity is a central force and therefore is <u>a conservative force</u>. This means:

1. The work performed by a gravitational force to move a body from a position A to a position B <u>only depends on these positions and not on the path followed to get from A to B. </u>

2. When the path that the body follows between A and B is a c<u>losed path or cycle</u> (as this case with a <u>circular orbit</u>), <u>the gravitational work is null or zero</u>.

<h2>This is because the gravity force that maintains an object in circular motion is a centripetal force, that is, <u>it always acts perpendicular to the movement</u>. </h2>

Then, in the case of the satellite orbiting the Earth in a circular orbit, its movement will always be perpendicular to the gravity force that attracts it to the planet, at each point of its path.

(d)  The total Mechanical Energy E of a body is the sum of its Kinetic Energy K and its Potential Energy P:

E=K+P     (8)

But in this specific case of the circular orbit, its kinetic energy will be expresses as calculated in the first answer (equation 5):

K_{m}=\frac{1}{2}Gm\frac{ME}{r}     (5)

And its potential energy due to the Earth gravitational field as:

P_{m}=-G\frac{mME}{r}     (9)

This energy is negative by definition.

So, the total mechanical energy of the orbit, also called the Orbital Energy is:

E=\frac{1}{2}Gm\frac{ME}{r}+(- G\frac{mME}{r})      (10)

Solving equation (10) we finally have the Orbital Energy:

E=-\frac{1}{2}mME\frac{G}{r}     (11)

At this point, it is necessary to clarify that a satellite (or any other celestial body) orbiting another massive body, can describe one of these types of orbits depending on its Orbital Total Mechanical Energy E:

-When E=0:

We are talking about an <u>open orbit</u> in which the satellite escapes from the attraction of the planet's gravitational field. The shape of its trajectory is a parabola, fulfilling the following condition:

K_{m}=-P_{m}

Such is the case of some comets in the solar system.

-When E>0:

We are also talking about <u>open orbits</u>, which are hyperbolic, being K_{m}>P_{m}

<h2>-When E: >>>><u>This case</u></h2>

We are talking about <u>closed orbits</u>, that is, the satellite will always be "linked" to the gravitational field of the planet and will describe an orbit that periodically repeats with a shape determined by the relationship between its kinetic and potential energy, as follows:

-Elliptical orbit: Although E is constant, K_m and P_m are changing along the trajectory .

-Circular orbit: When at all times both the kinetic energy K_m and the potential P_m remain constant, resulting in a total mechanical energy E as the one obtained in this exercise. This means that the speed is constant too and <u>is the explanation of why this Energy has a negative sign. </u>

3 0
3 years ago
A 75 kg baseball player runs at a velocity of 6 m/s before sliding to a stop at second base. a. What is the kinetic energy of th
lana [24]

Answer:

a. \displaystyle k_o=1350\ J

b. \displaystyle k_1=0\ J

c. \Delta k=-1350\ J

d. W=-1350\ J

e. F=-675\ N

Explanation:

<u>Work and Kinetic Energy </u>

When an object moves at a certain velocity v0 and changes it to v1, a change in its kinetic energy is achieved:

\Delta k=k_1-k_0

Knowing that

\displaystyle k=\frac{mv^2}{2}

We have

\displaystyle \Delta k=\frac{mv_1^2}{2}-\frac{mv_0^2}{2}

The work done by the force who caused the change of velocity (acceleration) is

\displaystyle W=\frac{mv_1^2}{2}-\frac{mv_0^2}{2}

If we know the distance x traveled by the object, the work can also be calculated by

W=F.x

Being F the force responsible for the change of velocity

The 75 kg baseball player has an initial velocity of 6 m/s, then he slides and stops

a. Before the slide, his initial kinetic energy is

\displaystyle k_o=\frac{mv_0^2}{2}

\displaystyle k_o=\frac{(75)6^2}{2}

\boxed{\displaystyle k_o=1350\ J}

b. Once he reaches the base, the player is at rest, thus his final kinetic energy is

\displaystyle k_1=\frac{(75)0^2}{2}

\boxed{\displaystyle k_1=0\ J}

c. The change of kinetic energy is

\Delta k=k_1-k_0=0\ J-1350\ J

\boxed{\Delta k=-1350\ J}

d. The work done by friction to stop the player is

W=\Delta k=k_1-k_0

\boxed{W=-1350\ J}

e. We compute the force of friction by using

W=F.x

and solving for x

\displaystyle F=\frac{W}{x}

\displaystyle F=\frac{-1350\ J}{2\ m}

\boxed{F=-675\ N}

The negative sign indicates the force is against movement

6 0
3 years ago
Other questions:
  • Select the correct answer.
    5·1 answer
  • What is the proper function of a linkage? *
    6·1 answer
  • 8. Contrast. The energy that can be released during a nuclear fission reaction with the energy that can be released during a nuc
    14·1 answer
  • A circular specimen of MgO is loaded using a three-point bending mode. Compute the minimum possible radius of the specimen witho
    5·1 answer
  • A remote control car is traveling at a velocity of 0.50 m/s when it hits a wall and comes to a stop in 0.050 seconds. What is th
    13·1 answer
  • Imagine a rock is dropped from the top of a tall building. After 2 seconds of falling, the rock’s instantaneous speed is approxi
    14·2 answers
  • A ball tied on a string rotates in a circular path as shown above. The only forces acting on the ball at any point are the weigh
    8·1 answer
  • What must be the reaction force when someone hits a tree with an axe?
    12·1 answer
  • Una barra de aluminio que esta a 78 GRADOS CENTIGRADOS entra en contacto con una barra de cobre de la misma longitud y área que
    8·1 answer
  • The toy car is about 3 inches long is an example of a ?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!