Below are four statements about acceleration. Which statement is not correct? A Acceleration always involves changing speed. B C
1 answer:
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Answer:
Explanation:
We define the linear density of charge as:
Where L is the rod's length, in this case the semicircle's length L = πr
The potential created at the center by an differential element of charge is:
where k is the coulomb's constant
r is the distance from dq to center of the circle
Thus.
Potential at the center of the semicircle
Given that,
The electric field is given by,
Suppose, B is the amplitude of magnetic field vector.
We need to find the complete expression for the magnetic field vector of the wave
Using formula of magnetic field
Direction of vector is the direction of propagation of the wave .
Direction of magnetic field =
We need to calculate the poynting vector
Using formula of poynting
Put the value into the formula
Hence, The poynting vector is
We must place the pivot to keep the meter stick in balance at 90 cm (10 cm from the weight) from the free end.
Answer: Option B
<u>Explanation:</u>
In initial stage, the meter stick’s mass and mass hanged in meter stick at one end are same. Refer figure 1, the mater stick’s weight acts at the stick’s mid-point.
If in case, the meter stick is to be at balanced form, then the acting torques sum would be zero. So,
Taking out ‘mg’ as common and we get
Hence, the stick should be pivoted at a distance of,
So, the stick should be pivoted at a distance of 75 cm at the free end
Now, replace mass with another mass. i.e., four times the initial mass (as given)
If in case, the meter stick is to be at balanced form, then the acting torques sum would be zero. So,
Taking out ‘mg’ as common and we get
Hence, the stick should be pivoted at a distance of,
So, the stick should be pivoted at a distance of 10 cm from the free end.
Therefore, the option B is correct 90 cm (10 cm from the weight).
