For the following question, two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the c
orrect answer to these questions from the codes (i), (ii), (iii) and (iv) as given below. i) Both A and R are true and R is correct explanation of the assertion. ii) Both A and R are true but R is not the correct explanation of the assertion. iii) A is true but R is false. iv)A is false but R is true. Assertion: Concave mirrors are used as reflectors in torches, vehicle head-lights and in search lights. Reason: When the object is placed beyond the centre of curvature of a concave mirror, the image formed is real and inverted.
please help
please help
1 answer:
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Answer:
a) FE = 0.764FG
b) a = 2.30 m/s^2
Explanation:
a) To compare the gravitational and electric force over the particle you calculate the following ratio:
(1)
FE: electric force
FG: gravitational force
q: charge of the particle = 1.6*10^-19 C
g: gravitational acceleration = 9.8 m/s^2
E: electric field = 103N/C
m: mass of the particle = 2.2*10^-15 g = 2.2*10^-18 kg
You replace the values of all parameters in the equation (1):
Then, the gravitational force is 0.764 times the electric force on the particle
b)
The acceleration of the particle is obtained by using the second Newton law:
you replace the values of all variables:
hence, the acceleration of the particle is 2.30m/s^2, the minus sign means that the particle moves downward.
Answer:
- <u><em>1. Part A: 648N</em></u>
- <u><em></em></u>
- <u><em>2. Part B: 324J</em></u>
- <u><em></em></u>
- <u><em>3. Part C: 1,296N</em></u>
Explanation:
<em><u>1. Part A:</u></em>
The magnitude of the force is calculated using the Hook's law:
You know but you do not have
.
You can calculate it using the equation for the work-energy for a spring.
The work done to compress the springs a distance is:
Where is the change in the elastic potential energy of the "spring".
Here you have two springs, but you can work as if they were one spring.
You know the work (81.0J) and the length the "spring" was compressed (0.250m). Thus, just substitute and solve for k:
In reallity, the constant of each spring is half of that, but it is not relevant for the calculations and you are safe by assuming that it is just one spring with that constant.
Now calculate the magnitude of the force:
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<u><em>2. Part B. How much additional work must you do to move the platform a distance 0.250 m farther?</em></u>
<u><em></em></u>
The additional work will be the extra elastic potential energy that the springs earn.
You already know the elastic potential energy when Δx = 0.250m; now you must calculate the elastic potential energy when Δx = 0.250m + 0.250m = 0.500m.
Therefore, you must do 324J of additional work to move the plattarform a distance 0.250 m farther.
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<em><u>3. Part C</u></em>
<u><em></em></u>
<u><em>What maximum force must you apply to move the platform to the position in Part B?</em></u>
The maximum force is when the springs are compressed the maximum and that is 0.500m
Therefore, use Hook's law again, but now the compression length is Δx = 0.500m