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3 years ago

The rock cycle _____.

2 answers:

4 0

B is the answer you need and i honestly got this question on a middle school test

you must be in different area then me

Vesnalui [34]3 years ago

3 0

Answer:

B. Changes and recycles Earth's rocks.

Explanation:

In the rock cycle:-

Rocks are formed when hot molten lava comes from mantle in the form of volcanoes. After sometime this lava cools down and form ROCK.

The rocks are of basically three types :- igneous, sedimentary and metamorphosed rocks.

These rocks are form and erodes in the form of dust and then again form out of lava.

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A solid, uniform disk of radius 0.250 m and mass 45.2 kg rolls down a ramp of length 5.40 m that makes an angle of 17.0° with th

serious [3.7K]

Explanation:

Given that,

Radius of the disk, r = 0.25 m

Mass, m = 45.2 kg

Length of the ramp, l = 5.4 m

Angle made by the ramp with horizontal, $\theta=17^{\circ}$

Solution,

As the disk starts from rest from the top of the ramp, the potential energy is equal to the sum of translational kinetic energy and the rotational kinetic energy or by using the law of conservation of energy as :

(a) $mgh=\dfrac{1}{2}mv^2+\dfrac{1}{2}I\omega^2$

h is the height of the ramp

$sin\theta=\dfrac{h}{5.4}$

$h=sin(17)\times 5.4=1.57\ m$

v is the speed of the disk's center

I is the moment of inertia of the disk,

$I=\dfrac{1}{2}mr^2$

$\omega=\dfrac{v}{r}$

$mgh=\dfrac{1}{2}mv^2+\dfrac{1}{2}\dfrac{1}{2}mr^2\times (\dfrac{v}{r})^2$

$gh=\dfrac{1}{2}v^2+\dfrac{1}{4}v^2$

$gh=\dfrac{3}{4}v^2$

$9.8\times 1.57=\dfrac{3}{4}v^2$

v = 4.52 m/s

(b) At the bottom of the ramp, the angular speed of the disk is given by :

$\omega=\dfrac{v}{r}$

$\omega=\dfrac{4.52}{0.25}$

$\omega=18.08\ rad/s$

Hence, this is the required solution.

4 0

3 years ago

La capital de Puerto Rico es _____.

velikii [3]

La capital de Puerto Rico es la ciudad "San Juan".

7 0

3 years ago

Read 2 more answers

Which of the following would have an effect on an object's mass?

ICE Princess25 [194]

None of the above

mass is measurement of how much stuff in inside something.
if you freeze or heat an object, you merely change the state of the object. the mass is conserved.
if you change the elevation, nothing happens to the mass. the stuff will not leave the object.
so it is None of the above

8 0

2 years ago

Jogging on hard surfaces with insufficiently padded shoes produces large forces in the feet and legs.

Step2247 [10]

Answer:

Part a)

$F = 15600 N$

Part b)

force is 21.2 times more than the weight of the person

Explanation:

Part a)

As it is given that the distance after which he stopped is given as

d = 1.50 cm

here finally it stops so final speed is given as

$v_f = 0$

initial speed is given as

$v_i = 6 m/s$

now by the equation of kinematics we know that

$v_f^2 - v_i^2 = 2a d$

$0^2 - 6^2 = 2(a)(0.015)$

$a = -1200 m/s^2$

Now the force on the leg is given as

$F = ma$

m = mass of leg = 13 kg

$F = (13 kg)(-1200 m/s^2)$

$F = 15600 N$

Part b)

Force due to weight of the object

$F_g = Mg$

here we know

M = 75.0 kg

$F_g = 75(9.81)$

$F_g = 735.75 N$

Now we know that the ratio of the weight with the force on leg is given as

$\frac{F}{F_g} = \frac{15600}{735.75} = 21.2 N$

so force is 21.2 times more than the weight of the person

5 0

3 years ago

If the frequency of this beam is increased while the intensity is held constant, does the number of electrons ejected per second

Ivan

Answer:

if the intensity of photons is constant then number of ejected electrons will remain same

Explanation:

As per photoelectric effect we know that when light of sufficient frequency fall on the surface of metal then electrons get ejected out of the surface with certain kinetic energy

Here the energy of photons is used to eject out the electrons from metal surface and to give the kinetic energy to the ejected electrons

so we have

$h\nu = W + KE$

here W = work function of metal which shows the energy required to eject out electrons from metal surface

KE = kinetic energy of ejected electrons

now if we increase the frequency of the photons that incident on the metal surface then in that case the incident energy will increase

So the electrons will eject out with more kinetic energy while if the number of photon is constant or the intensity of photons is constant then number of ejected electrons will remain same

8 0

3 years ago