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3 years ago

What can be absorbed or released as the result of a chemical reaction?

Physics

2 answers:

Artist 52 [7]3 years ago

8 0

Chemical reaction involves absorption or release of heat energy.

Lera25 [3.4K]3 years ago

3 0

Energy is released or absorbed ,but no loss in total molecules,each of which consists of one atom of oxygen and two of hydrogen,are broken down.!

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What is the torque τb about axis b due to the force f⃗ ? (b is the point at cartesian coordinates (0,b), located a distance b fr

yKpoI14uk [10]

Check the attached file for the solution.

8 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

3 years ago

The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275 kj/mol. What wavelength in nm of

denis23 [38]

Answer: 430 nm

Explanation:

For 257 kJ to dislodge one mole of electrons we need,

275 x 10^3 / 6 x 10^23 = 4.6 x 10^-19

Using Einstein’s relationship between energy, frequency and wavelength

E = hf = h x (c/landa)

Therefore

Landa = h x (c/E) = 6.6 x 10^-34 x (3 x 10^8 / 4.6 x 10^-19 = 4.3 x 10-7 m.

In nm, landa = 430 nm

7 0

4 years ago

Is acceleration a vector, scalar, both, neither

NemiM [27]

Answer: vector yes

Explanation:

Acceleration is a vector, and thus has a both a magnitude and direction. Acceleration can be caused by either a change in the magnitude or the direction of the velocity.

5 0

3 years ago

An electron and a proton are each placed at rest in a uniform electric field of magnitude 560 N/C. Calculate the speed of each p

Butoxors [25]

Answer:

The speed of electron is $v=4.52\times 10^6\ m/s$ and the speed of proton is 2468.02 m/s.

Explanation:

Given that,

Electric field, E = 560 N/C

To find,

The speed of each particle (electrons and proton) 46.0 ns after being released.

Solution,

For electron,

The electric force is given by :

$F=qE$

$F=1.6\times 10^{-19}\times 560=8.96\times 10^{-17}\ N$

Let v is the speed of electron. It can be calculated using first equation of motion as :

$v=u+at$

u = 0 (at rest)

$v=\dfrac{F}{m}t$

$v=\dfrac{8.96\times 10^{-17}}{9.1\times 10^{-31}}\times 46\times 10^{-9}$

$v=4.52\times 10^6\ m/s$

For proton,

The electric force is given by :

$F=qE$

$F=1.6\times 10^{-19}\times 560=8.96\times 10^{-17}\ N$

Let v is the speed of electron. It can be calculated using first equation of motion as :

$v=u+at$

u = 0 (at rest)

$v=\dfrac{F}{m}t$

$v=\dfrac{8.96\times 10^{-17}}{1.67\times 10^{-27}}\times 46\times 10^{-9}$

$v=2468.02\ m/s$

So, the speed of electron is $v=4.52\times 10^6\ m/s$ and the speed of proton is 2468.02 m/s. Therefore, this is the required solution.

6 0

4 years ago