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4 years ago

11

Identify the factors that cause melting and thus the formation of magma. Choose one or more: A. decompression B. compression C.

heat transfer D. rapid cooling E. addition of volatiles F. crystallization

1 answer:

nordsb [41]4 years ago

8 0

Answer: C Heat Transfer, E Addition of Volatiles and A Decompression

Explanation:

- Decompression melting takes place within Earth when a body of rock is held at approximately the same temperature but the pressure is reduced.

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a man drags a 8.10 kg bag of mulch at a constant speed, applying a 29.5 N at 38°. what is the coefficient of friction?

lesantik [10]

Answer:

The coefficient of friction is 0.38.

Explanation:

The free body diagram is drawn below.

Let $f$ be frictional force acting in the backward direction as shown. Let the coefficient of friction be $\mu$ . Let $N$ be the normal reaction force acting on the bag.

Given:

Mass of the bag is, $m=8.10\textrm{ kg}$

Force acting at $\theta = 38$ ° is $F= 29.5\textrm{ N}$

Acceleration due to gravity is, $g=9.8\textrm{ }m/s^{2}$

The force F can be resolved into its components as $F_{x}=F \cos \theta$ and $F_{y}=F \sin \theta$

Therefore,

$F_{x}=29.5\cos(38)=23.25\textrm{ N}\\F_{y}=29.5\sin(38)=18.16\textrm{ N}$

Now, as there is no acceleration in vertical direction, therefore,

Sum of upward forces = Sum of downward forces

$N+F_{y}=mg\\N=mg-F_{y}=8.10\times 9.8-18.16\\N=79.38-18.16=61.22\textrm{ N}$

Now, as the bag is moving at a constant speed, so acceleration in the horizontal direction is also zero as acceleration is the rate of change of velocity.

Therefore, backward force = forward force.

$f=F_{x}\\f=23.25\textrm{ N}$

Now, frictional force is given as:

$f=\mu N\\\mu = \frac{f}{N}=\frac{23.25}{61.22}=0.38$

Therefore, the coefficient of friction is 0.38.

8 0

4 years ago

Can someone please help?? I don’t understand this material!!!

Debora [2.8K]

Answer:

1)

When the person throws the ball away, the person rolls backward. This is due to the law of conservation of momentum: in fact, the total momentum of the person+ball system must be conserved.

At the beginning,

$p_i=0$

after throwing the ball, the total momentum is the sum of the momentum of the person and of the ball:

$p_f=p_p + p_b$

Since momentum is conserved,

$p_i = p_f\\0=p_p+p_b$

So

$p_p = -p_b$

Therefore, the person has equal momentum (in magnitude) but opposite direction to the ball, so the person rolls backward.

However, if the person hold to the ball, then they will have same momentum (moving in the same direction). In order to conserve the total momentum (which was zero at the beginning), the only possible solution is that

$p_p=p_b=0$

which means that both the person and the ball will remain at rest. This is because there are no external forces acting on the system, so the system cannot move.

2)

The change in momentum of an object is given by

$\Delta p=m(v-u)$

where

m is the mass of the object

v is its final velocity

u is the initial velocity

For the clay ball in this problem, we have:

m = 50 g = 0.050 kg

v = 0 m/s (it sticks on the wall)

u = 1 m/s

So its change in momentum is

$\Delta p_c=(0.050)(0-1)=-0.050 kg m/s$

For the superball, we have:

m = 50 g = 0.050 kg

v = -0.8 m/s (it bounces back)

u = 1 m/s

So its change in momentum is

$\Delta p_s = (0.050)(-0.8-1)=-0.09 kg m/s$

So, the superball has a greater change in momentum (in magnitude).

3a)

According to Newton's third law of motion:

"When an object A exerts a force (action force) on an object B, then object B exerts an equal and opposite force (reaction force) on object A".

Here, we have a Hummer and a Beetle colliding head-on: we can identify them as object A and object B. Therefore, according to Newton's third law:

- The action force is the force of impact exerted by the Hummer on the Beetle

- The reaction force is the force of impact exerted by the Beetle on the Hummer

And according to the Law, the two forces are equal in magnitude: so, the two vehicles experience the same force of impact.

3b)

The change in momentum of each vehicle during the collision can be written as

$\Delta p = F\Delta t$ (1)

where

$\Delta p$ is the change in momentum

$F$ is the force experienced by the vehicle

$\Delta t$ is the duration of the collision

in part 3a), we said that the two vehicles experience the same force in the collision.

Moreover, the duration of the collision, $\Delta t$ , is the same for the two vehicles.

As a result, according to formula (1), the two vehicles have same change in momentum (however, the directions would be opposite, since they experience force in opposite directions).

3c)

According to Newton's second law of motion, the acceleration of an object is given by:

$a=\frac{F}{m}$

where

F is the force experienced by the object

m is its mass

a is its acceleration

In part 3a), we stated that the force experienced by the Beetle and the Hummer is the same. However, the mass of the Beetle is smaller than the mass of the Hummer: from the equation we see that the acceleration is inversely proportional to the mass, therefore the Beetle will experience a greater acceleration.

4a)

The force experienced by the dashboard on the car is given by:

$F=\frac{\Delta p}{\Delta t}$

Where

$\Delta p$ is the change in momentum

$\Delta t$ is the duration of the collision

In a padded dashboard, the duration of the collision $\Delta t$ is larger than the duration of the collision for a hard dashboard. According to the equation above, the force experienced by the dashboard (and so, the car) is inversely proportional to the duration of the collision: therefore, since the padded dashboard has a larger $\Delta t$ , it will experience a smaller force than the hard dashboard.

4b)

The force experienced by the climber if falling is given by

$F=\frac{\Delta p}{\Delta t}$

Where

F is the force experienced by the climber

$\Delta p$ is his change in momentum

$\Delta t$ is the duration of fall

Nylon is a very elastic material, so it is able to "soften" the fall by stretching a lot. As a result, the nylon increases the value of $\Delta t$ in the formula. Since the force experienced by the climber is inversely proportional to $\Delta t$ , the climber will feel less force thanks to the nylon.

4c)

This technique is used to exploit the "push" given by the second car of the train to the first car when the brakes are applied.

At first, the engine is started, and the first car starts accelerating, pulling the second car (and the following cars). Then, the brakes are applied on the first car: however, the second car keeps moving by inertia, so then it gives a push forward on the first car. Then, this action is repeated several times, so that this push exerted by the second car is exploited several times.

3 0

3 years ago

If two forces act on an object, what is the relationship between the two forces? (pls explain)

Westkost [7]

Answer:

B. The larger force causes more acceleration than the smaller.

Explanation:

For example, let me use a child and a grown up. The child represents the smaller force while the grown up represents the larger force. If they are pushing the same object of different sides, obviously the side with the grown up will push and move to the side of the child because it is stronger.

3 0

2 years ago

If mr galans paces is equal to 1.8 m,how many paces would it take to get to the moon

Anettt [7]

Answer:

The number of paces it would take to get to the Moon is 213,555,556 paces

Explanation:

The given length of Mr Galan's paces = 1.8 m/pace

The distance from the Earth to the Moon is, 384,400 km = 384,400,000 m

Therefore, the number of paces, "n", it would take to get to the Moon from the Earth is given as follows;

n = (The distance from the Earth to the Moon)/(The length of each Mr Galan's paces)

∴ n = 384,400,000 m/(1.8 m/pace) = 213,555,556 paces

The number of paces it would take to get to the Moon = n = 213,555,556 paces

5 0

3 years ago

What happens when an electron returns to its ground state from its excited state

Norma-Jean [14]

Answer: Energy is released by the electron in the form of light

Explanation:

Let's start by explaining that each atom in its natural state has a specific structure of its energy levels. Where <u>the lowest energy level is called the </u><u>ground state</u><u>. </u>

<u> </u>

So, when an atom is in its ground state, its electrons fill the lower energy orbitals completely before they begin to occupy higher energy orbitals.

Then, when an atom is excited, it means that it has left its ground state (in which each electron occupies its place in its orbit, around the nucleus), when this happens some electron jumps out of the orbit it occupied in its fundamental state to an outer orbit, further away from the nucleus <u>and then return to the ground state, emitting in the form of light the energy received.</u>

To understand it better:

An excited electron is an unstable electron, and when passing from one orbit to another, it produces light of a specific wavelength (color) that depends on the amount of energy the electron loses.

5 0

4 years ago