I believe your answer is off by a couple of decimal points. The answer is approximately 1.041 N
Explanation:
First, we will calculate the electric potential energy of two charges at a distance R as follows.
R = 2r
=
= 0.2 m
where, R = separation between center's of both Q's. Hence, the potential energy will be calculated as follows.
U =
=
= 0.081 J
As, both the charges are coming towards each other with the same energy so there will occur equal sharing of electric potential energy between these two charges.
Therefore, when these charges touch each other then they used to posses maximum kinetic energy, that is, .
Hence, K.E =
=
= 0.0405 J
Now, we will calculate the speed of balls as follows.
V =
=
= 0.142 m/s
Therefore, we can conclude that final speed of one of the balls is 0.142 m/s.
Answer:
L = L0 (1 + c T) where c is the coefficient and T the change in temperature
L = 50 ( 1 + 2.05E-6 * 50) = 50.0051 cm
<span> For any body to move in a circle it requires the centripetal force (mv^2)/r.
In this case a ball is moving in a vertical circle swung by a mass less cord.
At the top of its arc if we draw its free body diagram and equate the forces in radial
direction to the centripetal force we get it as T +mg =(mv^2)/r
T is tension in cord
m is mass of ball
r is length of cord (radius of the vertical circle)
To get the minimum value of velocity the LHS should be minimum. This is possible when T = 0. So
minimum speed of ball v at top =sqrtr(rg)=sqrt(1.1*9.81) = 3.285 m/s
In the second case the speed of ball at top = (2*3.285) =6.57 m/s
Let us take the lowest point of the vertical circle as reference for potential energy and apllying the conservation of energy equation between top & bottom
we get velocity at bottom as 9.3m/s.
Now by drawing the free body diagram of the ball at the bottom and equating the net radial force to the centripetal force
T-mg=(mv^2)/r
We get tension in cord T=13.27 N</span>