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2 years ago

How should you behave while performing laboratory experiments?

Physics

2 answers:

Brrunno [24]2 years ago

4 0

Explanation:

Always behave responsibly in the laboratory. Do not run around or play practical jokes. Always check the safety data of any chemicals you are going to use. Never smell, taste or touch chemicals unless instructed to do so.

anygoal [31]2 years ago

3 0

Do not run around. Always check the safety data of any chemicals you are going to use. Never smell, taste or touch chemicals unless instructed to do so (if smelling only waft it.)

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The layer of the Earth that is composed of large plates that interlock and move over time is the _______. asthenosphere lithosph

siniylev [52]

The lithosphere because it includes the outer region of the earth including the crust and outer mantle

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2 years ago

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A thermometer initially reading 212F is placed in a room where the temperature is 70F. After 2 minutes the thermometer reads 125

frez [133]

Answer:

91.3°F

Explanation:

Let T be the temperature of the thermometer at any time

T∞ be the temperature of the room = 70°F

T₀ be the initial temperature of the thermometer = 212°F

And m, c, h are all constants from the cooling law relation

From Newton's law of cooling

Rate of Heat loss by the cake = Rate of Heat gain by the environment

- mc (d/dt)(T - T∞) = h (T - T∞)

(d/dt) (T - T∞) = dT/dt (Because T∞ is a constant)

dT/dt = (-h/mc) (T - T∞)

Let (h/mc) be k

dT/(T - T∞) = -kdt

Integrating the left hand side from T₀ to T and the right hand side from 0 to t

In [(T - T∞)/(T₀ - T∞)] = -kt

(T - T∞)/(T₀ - T∞) = e⁻ᵏᵗ

(T - T∞) = (T₀ - T∞)e⁻ᵏᵗ

Inserting the known variables

(T - 70) = (212 - 70)e⁻ᵏᵗ

(T - 70) = 142 e⁻ᵏᵗ

At t = 2 minute, T = 125°F

125 - 70 = 142 e⁻ᵏᵗ

55/142 = e⁻ᵏᵗ

- kt = In (55/142) = In (0.3873)

- k(2) = - 0.9485

k = 0.4742 /min

At time t = 4 mins

kt = 0.4742 × 4 = 1.897

(T - 70) = 142 e⁻ᵏᵗ

e^(-1.897) = 0.15

T - 70 = 142 × 0.15 = 21.3

T = 91.3°F

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3 years ago

Which phrase best describes wave motion

White raven [17]

Answer:

I would describe wave motion as “propagating oscillations” as a general phrase.

For something like water waves, I would say “water waves are oscillations of the surface of a body of water that propagate in a given direction.”

For electromagnetic waves I would say “An electromagnetic wave is an oscillating disturbance of the electric and magnetic fields that propagates through space.”

Explanation:

PLZ MARK BRAINLIEST

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2 years ago

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Why is it important for earth’s magnetic field that the inner core is hotter then the outer core?

Shkiper50 [21]

A. The inner core heat produce stuff

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2 years ago

What are the first two steps for finding the magnitude of the resultant vector?

Marina86 [1]

Answer:

In the analytical method,

Resolve the vectors into the perpendicular components of the Cartesian coordinates.
Calculate the magnitude of the resultant vector using the Pythagoras theorem.

Explanation:

There are two methods to find the magnitude of the resultant vector.
One is the geometrical method and the other one is the analytical method.
In the geometrical method, all the vectors are connected the head to tail with the appropriate magnitude and the resultant vector is obtained by joining the initial point and the final point by a vector in the reverse direction. The magnitude of the resultant vector is given by the length of the line.
In the analytical method, all the vectors are resolved into the perpendicular components.
Using Pythagoras theorem, the magnitude of the resultant vector can be obtained
If A and B are the two vectors forming an angle ∅ between them, then the magnitude of the resultant vector is given by the formula

$R=\sqrt{A^{2}+B^{2}+2ABcos\phi}$

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2 years ago

How should you behave while performing laboratory experiments?​

How should you behave while performing laboratory experiments?