Answer:
Explanation:
As the source is situated on x - axis , it must be situated in between the two listeners .
So the x coordinate of source is
(-7 + 3 )/2
= - 2 m
The equation of the wave- front will be that o a circle having centre at (-2,0)
and radius = distance between -2 and 3 , that is 5 m
equation of circle
=( x+2 )² + y² = 25
It cuts y axis when x = 0
Putting x = 0
4 + y² = 25
y² = 21
y = + √21 , or - √21
Answer:

Explanation:
Given data
Electric potential at point a is Ua=5.4×10⁻⁸J
q₂ moves to point b where a negative work done on it
Required
Electric potential energy Ub
Solution
When a particle moves from a point where the potential is Ua to a point where it is Ub the change in potential energy is equal to work done where the force exerted on the charge is conservative and work done is given by:

Now substitute the given values
So

I think its B or D, most likely D.
Answer:

Explanation:
Given that
Constant rate of leak =R
Mass at time T ,m=RT
At any time t
The mass = Rt
So the total mass in downward direction=(M+Rt)
Now force equation
(M+Rt) a =P- (M+Rt) g

We know that





This is the velocity of bucket at the instance when it become empty.
Answer:
Given,
mass of man = 100 N = 10 kg
height = h = 25m
since the man does not move anything with his force, work done by him is zero
work done on the man = gain in potential energy
P.E=mgh
P.E=10×9.8×25
P.E=2.45KJ
Explanation:
so, potential energy gained by man is 2.45 KJ