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2 years ago

Which of the following is true about the Earth's natural resources?

Physics

1 answer:

Art [367]2 years ago

4 0

The last answer is the only correct one. Do you want to know why or were you just checking?

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What are some superheroes that resemble neurotransmitter functions. Dopamine: Acetylcholine: Endorphins: GABA: Glutamates: Norep

dezoksy [38]

Answer:

Serotonin

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2 years ago

A billiard ball of mass 0.28 kg hits a second, identical ball at a speed of 7.2 m/s and comes to rest as the second ball flies o

GaryK [48]

Answer:

(a) -8064 N

(b) 8064 N

Explanation:

(a)

From Newton’s law of motion, Force, F=ma where m is mass and a is acceleration.

Since acceleration is the rate of change of velocity per unit time, then where v is velocity and the subscripts f and I denote final and initial

For the first ball, the mass is 0.28 Kg, final velocity is zero since it finally comes to rest, t is 0.00025 s and initial velocity is given as 7.2 s. Substituting these values we obtain

$F=0.28\times \frac {0-7.2}{0.00025}=-8064 N$

(b)

For the second ball, the mass is also 0.28 Kg but its initial velocity is taken as zero, the final velocity of the second ball will be equal to the initial velocity of the second ball, that is 7.2 m/s and the time is also same, 0.00025 s. By substitution

$F=0.28\times \frac {7.2-0}{0.00025}=8064 N$

Here, we prove that action and reaction are equal and opposite

7 0

2 years ago

Which would show an example of how physical changes are reversible? cutting a gold bar in two pieces and then putting the pieces

arlik [135]

Melting tin and then cooling it into a mold is an example of reversible physical changes.

<u>Explanation:</u>

When an object undergoes a change in size, state, or shape and not in their chemical compositions referred to as physical change. But chemical change occurs as a result of the change in substances composition. It also forms a new one by the combination/ breakage of one or more objects.

In the case of making gold cube into two pieces, there is no possibility of getting the original state again even the physical change happens. Match burning and relighting and sodium plus chlorine forming table salt show chemical change. But in tin melting and cooling it to form mold is the physical change i.e changes in state(liquid to solid) and are reversible too.

6 0

2 years ago

Read 2 more answers

Please help, I’m confused

riadik2000 [5.3K]

Answer:

1 is the correct answer plz mark me as branilest answer

4 0

2 years ago

If a car accelerates at an average rate of 7.92 m/s2. Calculate how long it takes the car to speed up from 6.38 m/s to 34.86 m/s

blondinia [14]

$a = \dfrac{\Delta v}{\Delta t} \\~\\~\\a = \dfrac{v-v_0}{\Delta t} \\~\\~\\7.92 = \dfrac{34.86-6.38}{\Delta t} \\~\\~\\\Delta t = \dfrac{2848}{792} \\~\\~\\ \Delta t = 3+\dfrac{472}{792} \\~\\~\\\Delta t = 3+\dfrac{2^3\cdot(59)}{2^3\cdot(99)} \\~\\~\\\Delta t = 3 + 0.5959\cdots \\~\\~\\\Delta t \approx 3.6$

It takes aproximately 3.6 secs

5 0

2 years ago

Read 2 more answers