Answer:
D
Explanation:
From the information given:
The angular speed for the block 
Disk radius (r) = 0.2 m
The block Initial velocity is:

Change in the block's angular speed is:

However, on the disk, moment of inertIa is:

The time t = 10s
∴
Frictional torques by the wall on the disk is:

Finally, the frictional force is calculated as:


Answer: ![-\frac{1}{2}\times \frac{d[Br^.]}{dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%5Cfrac%7Bd%5BBr%5E.%5D%7D%7Bdt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
Explanation:
Rate of a reaction is defined as the rate of change of concentration per unit time.
Thus for reaction:

The rate in terms of reactants is given as negative as the concentration of reactants is decreasing with time whereas the rate in terms of products is given as positive as the concentration of products is increasing with time.
![Rate=-\frac{d[Br^.]}{2dt}](https://tex.z-dn.net/?f=Rate%3D-%5Cfrac%7Bd%5BBr%5E.%5D%7D%7B2dt%7D)
or ![Rate=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=Rate%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
Thus ![-\frac{d[Br^.]}{2dt}=+\frac{d[Br_2]}{dt}](https://tex.z-dn.net/?f=-%5Cfrac%7Bd%5BBr%5E.%5D%7D%7B2dt%7D%3D%2B%5Cfrac%7Bd%5BBr_2%5D%7D%7Bdt%7D)
The increase in potential energy of his mother if her mass is 56.0 kg will be 6031.97 J.
<h3>What is gravitational potential energy?</h3>
The energy that an item has due to its location in a gravitational field is known as gravitational potential energy.
The potential energy increases by 3773 J
PE₂-PE₁=mg(h₂-h₁)
3773 J = 35.0 × 9.81 × (h₂-h₁)
(h₂-h₁) = 10.98
Case 2 ;
ΔPE =?
ΔPE=mg(h₂-h₁)
ΔPE=56.0 × 9.81 ×10.98
ΔPE=6031.97 J.
Hence, the increase in potential energy of his mother if her mass is 56.0 kg will be 6031.97 J.
To learn more about the gravitational potential energy, refer;
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The vertical force exerted on the lawn is 68.8 N downward
Explanation:
The vertical force exerted by the lawnmower on the lawn is equal to the vertical component of the force applied, therefore:

where
F is the magnitude of the force applied
is the angle between the direction of the force and the horizontal
In this problem:
F = 120 N
Substituting,

where the negative sign means the direction of the force is downward.
Learn more about vector components and forces here:
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The energy of a wave will remain constant if which of the following changes are made to it is given below
Explanation:
1.In electromagnetic waves, energy is transferred through vibrations of electric and magnetic fields. In sound waves, energy is transferred through vibration of air particles or particles of a solid through which the sound travels. In water waves, energy is transferred through the vibration of the water particles.
2.First of all for light which is a electromagnetic wave c=frequency*wavelength. As the wavelength increases the frequency decreases. This can be physically understood as the increase in red shift of the light. Also energy =h*frequency,hence increasing wavelength decreases the energy carried by the photon.
3.Wave frequency is related to wave energy. the more energy in a wave, the higher its frequency. The lower the frequency is, the less energy in the wave.