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4 years ago

Which method of separation can be used for a heterogeneous mixture?

1 answer:

7 0

Heterogeneous mixture refers to a mixture consisting of various components and sizes. The mixture does not appear as a uniform composition.

Hence to separate it, we will make use of the different sizes and weights.

So it is by their densities. (B)

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I just don't know how to do the question (a) and (b)

ozzi

Using the equation

$F=ma$

we can observe that you have to apply a non-zero net force to an object in order to make it accelerate. In fact, if the net force is zero you have

$0=ma \iff a=0$

Since we're assuming $n\neq 0$

Now, if the 12N force is applied, the object moves with a constant speed. A constant speed means no acceleration, since by definition the acceleration is a change in speed.

If this sounds counterintuitive to you (why I'm applying a force but I have to acceleration?) think of when we drive a car: even if you want to keep your speed constant, you still have to use the gas pedal, just enough so that the push of the motor balances exactly the road/wheels friction. If you give less gas, the friction becomes stronger, and the car slows down. If you give more gas, the motor push becomes stronger, and the car accelerates.

Back to your exercise: constant speed means to acceleration, so the net force must be zero. This implies that the friction force is exactly 12N.

If the force is increased to 18N, there will be a net force of 6N pushing the object, causing it to accelerate. Using again the same equation of before, and plugging the 3kg mass in the equation, we have

$F=ma \iff 6=3a \iff a=2$

So, the object moves with constant acceleration and initial speed of 10m/s for 0.2 seconds. It's final speed will be

$v = v_0+at = 10+2\cdot 0.2 = 10.4$

5 0

4 years ago

In comparing molar specific heat for gases under constant pressure CP and constant volume CV, we conclude that (more than one co

Sauron [17]

Answer:

b. Specific heat increases as the number of atoms per molecule increases.

c. Specific heat at constant pressure is higher than at constant volume.

d. Monatomic gases behave like ideal gases.

Explanation:

Specific heat of the gas at constant pressure is usually higher than that of the volume.

i.e.

Cp - Cv = R

where R is usually the gas constant.

However, monoatomic gases are gases that exhibit the behavior of ideal gases. This is due to the attribute of the intermolecular forces which plays a negligible role. Nonetheless, the case is not always true for all temperatures and pressure.

Similarly, the increase in the number of atoms per molecule usually brings about an increase in specific heat. This effect is true as a result of an increase in the total number associated with the degree of freedom from which energy can be separated.

Thus, from above explanation:

Option b,c,d are correct while option (a) is incorrect.

4 0

3 years ago

Use Newton's laws to explain why a falling object dropped from a 57m tower accelerates initially but then reaches constant veloc

snow_lady [41]

Answer:

At the point of dropping the object, by Newton's first law due to gravitational force $F_g$ = m × g, accelerates

By Newton's Second law the object reaches impacts on the air with the gravitational force resulting in changing momentum of m×(Final Velocity - Initial Velocity)

As the velocity increases, the rate of change of momentum becomes equivalent to the gravitational force and by Newton's third law, the action action and reaction are equal and opposite hence they cancel each other out

The body then moves at a constant uniform motion down according to Newton's first law

Explanation:

At the point the object of mass, m, is dropped from the height of the tower, the only force acting on the object is the gravitational force such that the object has an acceleration which is the acceleration due to gravity, g, and the gravitational force is therefore = m × g

As the speed of the object increases while the object is falling with the gravitational acceleration the rate at which the object cuts through layers of air which (by Newton's first law of motion, are at rest ) has some buoyancy effect also increases therefore, the object is constantly increasingly changing the momentum of the air which by Newton's second law results, at an high enough velocity, and by Newton's third law, in a force equal to the applied gravitational force

Therefore, the force of the air drag becomes equal to the gravitational force, cancelling each other out and the object then moves according to Newton;s first law, in uniform motion of a constant speed while still falling down.

5 0

3 years ago

Which of the following is a type of T cell?

Bess [88]

Answer:

Explanation:

7 0

3 years ago

Read 2 more answers

Suppose we have two planets with the same mass, but the radius of the second one is twice the size of the first one. How does th

bogdanovich [222]

The free-fall acceleration on the second planet is one-fourth the value of the first planet.

Calculation:

Consider the mass of planet A to be, M

the mass of planet B to be, Mₓ = M

the radius of planet A to be, R₁

the radius of planet B to be, R₂

The acceleration due to gravity on planet A's surface is given as:

g = GM/R₁² - (1)

Similarly, the acceleration due to gravity on planet B's surface is given as:

g' = GM/R₂² [where, R₂ = 2R₁]

= GM/4R₁² -(2)

From equation 1 & 2, we get:

g/g' = GM/R₁² ÷ GM/4R₁²

g/g' = 4/1

Thus we get,

g' = 1/4 g

Therefore, the free-fall acceleration on the second planet is one-fourth the value of the first planet.

Learn more about free-fall here:

<u>brainly.com/question/13299152</u>

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6 0

2 years ago