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2 years ago

Ther are several differences between chemical and physical changes. Which process is an example of a chemical change?

Physics

2 answers:

Naddika [18.5K]2 years ago

6 0

Answer: Fire

Explanation: There are lots of different types of chemical changes but fire is the best example and almost always used in text books and tests. Fire, or "combustion" completely changes the fuel. It is a chemical reaction that produces heat and light energy in exchange for fuel and O2.

slamgirl [31]2 years ago

4 0

Answer:

A physical change is the change of the shape or color.

Explanation:

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an eagle has a mass of 8 kg and is flying 85 m above he ground with a speed of 20 m/s. what is the total mechanical energy of th

antoniya [11.8K]

85+5=90 :DD
90-20=70 :DDD

Good lessons.

5 0

3 years ago

Use the work-energy theorem to determine the force required to stop a 1000 kg car moving at a speed of 20.0 m/s if there is a di

Vlad1618 [11]

Answer:

4.44 kN in the opposite direction of acceleration.

Explanation:

Given that, the initial speed of the car is, $u=20m/s$

And the mass of the car is, $m=1000 kg$

The total distance covered by the car before stop, $s=45m$

And the final speed of the car is, $u=0m/s$

Now initial kinetic energy is,

$KE_{i}=\frac{1}{2}mu^{2}$

Substitute the value of u and m in the above equation, we get

$KE_{i}=\frac{1}{2}(1000kg)\times (20)^{2}\\KE_{i}=20000J$

Now final kinetic energy is,

$KE_{f}=\frac{1}{2}mv^{2}$

Substitute the value of v and m in the above equation, we get

$KE_{f}=\frac{1}{2}(1000kg)\times (0)^{2}\\KE_{i}=0J$

Now applying work energy theorem.

Work done= change in kinetic energy

Therefore,

$F.S=KE_{f}-KE_{i}\\F\times 45=(0-200000)J\\F=\frac{-200000J}{45}\\ F=-4444.44N\\F=-4.44kN$

Here, the force is negative because the force and acceleration in the opposite direction.

6 0

2 years ago

The copper wire and bulb is connected in a series with 220 V electric supply. Why only an electric bulb glows where as the coppe

Sveta_85 [38]

-- In a series circuit, the current ( I ) is the same at every point.

-- The power dissipated by any section of the circuit is I² x Resistance.

-- The wire has very low resistance, so I²R is very low dissipated power.

-- The filament in the bulb has most all of the resistance in the circuit,
so it dissipates virtually all the power of the circuit, and certainly much
more than the wires do.

7 0

3 years ago

Question 6 of 10

user100 [1]

Answer:

the answer is c

Explanation:

8 0

3 years ago

Read 2 more answers

You have gathered information about which websites your classmates visit to research science questions. What type of graph would

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