v = speed of the source of sound or the train towards the listener or switchman = 40 m/s
V = actual speed of sound = 340 m/s
f = actual frequency of sound as emitted from source or the train = 1000 Hz
f' = frequency as observed by the listener or by switchman = ?
Using Doppler's law , frequency observed by a listener from a source moving towards it is given as
f' = V f /(V - v)
inserting the values
f' = 340 x 1000 /(340 - 40)
f' = 340 x 1000/300
Answer:
the only effect it has is to create more induced charge at the closest points, but the net face remains zero, so it has no effect on the flow.
Explanation:
We can answer this exercise using Gauss's law
Ф = ∫ e . dA =
/ ε₀
field flow is directly proportionate to the charge found inside it, therefore if we place a Gaussian surface outside the plastic spherical shell. the flow must be zero since the charge of the sphere is equal induced in the shell, for which the net charge is zero. we see with this analysis that this shell meets the requirement to block the elective field
From the same Gaussian law it follows that if the sphere is not in the center, the only effect it has is to create more induced charge at the closest points, but the net face remains zero, so it has no effect on the flow , so no matter where the sphere is, the total induced charge is always equal to the charge on the sphere.









☯ <u>Using 1st equation of motion </u>











☯ <u>Now, Finding the force exerted </u>







☯ <u>Hence</u>, 

Answer:
6.96 s
Explanation:
<u>Given:</u>
- u = initial speed of the automobile = 0 m/s
- a = constant acceleration of the automobile =

- v = constant speed of the truck = 8.7 m/s
<u>Assume:</u>
- t = time instant at which the automobile overtakes the truck.
At the moment the automobile and the truck both meat each other the distance travel by both vehicles must be the same.

Since t = 0 s is the initial condition. So, they both meet again at t = 6.96 s such that the automobile overtakes the truck.