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3 years ago

What is the difference between a physical change and a chemical change

2 answers:

6 0

A physical change in something doesn't change what the it is. For example, if you break glass, it will still be glass. In a chemical change where there is a chemical reaction, a new thing is formed and energy is either given off or absorbed. For example, when you burn a log. The carbon in the log is reacting to the oxygen to create ashe and smoke

Aleks [24]3 years ago

4 0

physical rearranges molecules but doesn't affect their internal structures while chemical <span>is any change that results in the formation of new chemical substances</span>

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A 2-kg toy car accelerates from 0 to 5 m/s2. It

yan [13]

10 joules of work is done by the object

8 0

2 years ago

We wrap a light, nonstretching cable around a 8.00 kg solid cylinder with diameter of 30.0 cm. The cylinder rotates with negligi

antoniya [11.8K]

Answer:

h = 16.67m

Explanation:

If the kinetic energy of the cylinder is 510J:

$Kc=510=1/2*Ic*\omega c^2$

$\omega c=\sqrt{510*2/Ic}$

Where the inertia is given by:

$Ic=1/2*m_c*R_c^2=1/2*(8)*(0.15)^2=0.0225kg.m^2$

Replacing this value:

$\omega c=106.46rad/s$

Speed of the block will therefore be:

$V_b=\omega_c*R_c=106.46*0.15=15.969m/s$

By conservation of energy:

Eo = Ef

Eo = 0

$Ef = 510+1/2*m_b*V_b^2-m_b*g*h$

So,

$0 = 510+1/2*m_b*V_b^2-m_b*g*h$

Solving for h we get:

h=16.67m

3 0

3 years ago

If a light ray from a candle strikes a mirror at an angle of 40° with the normal, at what angle will the ray reflect?

pav-90 [236]

Answer:

the correct answer is b: 25

8 0

2 years ago

A circular coil of radius r = 5 cm and resistance R = 0.2 is placed in a uniform magnetic field perpendicular to the plane of th

Yuri [45]

Answer:

the question is incomplete, the complete question is

"A circular coil of radius r = 5 cm and resistance R = 0.2 ? is placed in a uniform magnetic field perpendicular to the plane of the coil. The magnitude of the field changes with time according to B = 0.5 e^-t T. What is the magnitude of the current induced in the coil at the time t = 2 s?"

2.6mA

Explanation:

we need to determine the emf induced in the coil and y applying ohm's law we determine the current induced.

using the formula be low,

$E=-\frac{d}{dt}(BACOS\alpha )\\$

where B is the magnitude of the field and A is the area of the circular coil.

First, let determine the area using $\pi r^{2} \\$ where r is the radius of 5cm or 0.05m

$A=\pi *(0.05)^{2}\\ A=0.00785m^{2}\\$

since we no that the angle is at $0^{0}$

we determine the magnitude of the magnetic filed

$B=0.5e^{-t} \\t=2s$

$E=-(0.5e^{-2} * 0.00785)$

$E=-0.000532v\\$

the Magnitude of the voltage is 0.000532V

Next we determine the current using ohm's law

$V=IR\\R=0.2\\I=\frac{0.000532}{0.2} \\I=0.0026A$

$I=2.6mA$

6 0

3 years ago

A wave of frequency 90 mega in 3 micro seconds. Calculate its wave length. hertz travels 6 km

gladu [14]

the wavelength is 2.2m

wavelength can be calculated by formula wavelength = velocity / frequency so here first we need to find the velocity so velocity is distance travelled/time taken that 2 X 10^8 m/s now wavelength is = 2 X 10^8/ 90=2.2m.

Waves are signals that can go through various media, including wire in the case of an electrical AC current, water, light, and other media. The separation between two identical points on a sinusoidal wave is known as the wavelength. You can determine how long there is between each wave's peak and each wave's trough if you know the frequency of the wave moving through the medium.

To learn more about wavelength:

brainly.com/question/13533093

#SPJ4

3 0

1 year ago