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Ratling [72]
2 years ago
10

In Kevin study he knows that each participant has an equal probability of being placed into each of his conditions Kevin must ha

ve used
Physics
1 answer:
kodGreya [7K]2 years ago
5 0

Answer:

Kevin must have used simple random sampling.

Explanation:

We can say that Kevin used simple random sampling. This is because this type of sampling allows elements to be taken from a population in a completely random way, to form a sample. In this case, each element, or individual, as shown in the question above, has the same probability of being selected to compose the sample, since this selection is completely random.

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What would make oppositely charged objects attract each other more?
Elina [12.6K]

Answer:

a: increasing the positive charge of the positively charged object and increasing the negative charge of the negatively charged object

Explanation:

5 0
3 years ago
What happens to the temperature of a substance when it is changing state of matter?
noname [10]
Solid substances have molecules held tightly and close together
Liquid substances have molecules moving loosely
Gaseous molecules are moving completely freely

As moleclues get further apart, i.e. As a substance changes state from solid to liquid to gas, molecules gain kinetic energy and vibrate/move more. This means they gain heat energy (the averge energy a substance has) so the temperature increases

Substances exist in different states at different temperatures and different substances will exist in different states at the same temperature. This is to do with the forces between molecules and how much heat (energy) is required to break them
5 0
3 years ago
Both lead and zinc are formed as precipitates. Which of these is a step in the formation of the minerals?
Ahat [919]
Minerals are naturally occurring inorganic (they're not formed from amino acids, peptides, or enzymes) chemical compounds.

From the given options, the following describes a step in the formation of the minerals: materials break up due to rise in temperature.

Correct answer: D

5 0
3 years ago
Newton’s empirical law of cooling/warming of an object is given by ( ), T Tm k dt dT = − where k is a constant of proportionalit
pychu [463]

Answer:

The time for the cake to cool off to room temperature is

approximately 30 minutes.

Let T_{0} = 70^{0}F be the temperature and T that of the body

Explanation:

 Our Tm = 70, the initial-value problem is

\frac{DT}{dt} = <em>k</em>(T − 70), T(0) = 300

Solving the equation, we get

\frac{DT}{t-70} = <em>kdt</em>

In [T-70]= <em>kt </em>+C_{1}

    T   =  70  + C_{2} e^{kt}

Finding he value for C_{2} using the initial value of T (0)= 300, therefore we get:

300=70+C_{2}

C_{2} = 230 therefore

T= 70+ 230 e^{kt}

Finding the value for <em>k </em>using T (3)  = 200, therefore we get

T (3) = 200

e^{3k} = \frac{13}{23}

<em>K </em>= \frac{1}{3} in \frac{13}{23}

= -0.19018

Therefore

T(t) = 70+230e^{-0.19018}

4 0
3 years ago
A 3.91 kg cart is moving at 5.7 m/s when it collides with a 4 kg cart which was at rest. They collide and stick together.
Nesterboy [21]

Answer:

<em>The velocity after the collision is 2.82 m/s</em>

Explanation:

<u>Law Of Conservation Of Linear Momentum </u>

It states the total momentum of a system of bodies is conserved unless an external force is applied to it. The formula for the momentum of a body with mass m and speed v is  

P=mv.  

If we have a system of two bodies, then the total momentum is the sum of the individual momentums:

P=m_1v_1+m_2v_2

If a collision occurs and the velocities change to v', the final momentum is:

P'=m_1v'_1+m_2v'_2

Since the total momentum is conserved, then:

P = P'

Or, equivalently:

m_1v_1+m_2v_2=m_1v'_1+m_2v'_2

If both masses stick together after the collision at a common speed v', then:

m_1v_1+m_2v_2=(m_1+m_2)v'

The common velocity after this situation is:

\displaystyle v'=\frac{m_1v_1+m_2v_2}{m_1+m_2}

There is an m1=3.91 kg car moving at v1=5.7 m/s that collides with an m2=4 kg cart that was at rest v2=0.

After the collision, both cars stick together. Let's compute the common speed after that:

\displaystyle v'=\frac{3.91*5.7+4*0}{3.91+4}

\displaystyle v'=\frac{22.287}{7.91}

\boxed{v' = 2.82\ m/s}

The velocity after the collision is 2.82 m/s

6 0
2 years ago
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