Answer:

Explanation:
Let the child is moving with speed same as the speed of water flow
So here the position of child with respect to flow must be zero
And if the boat start at an angle with the vertical
so its relative speed with flow of water is given as


now the time to reach the child is given as

so now we have

So the time to catch the child is given as


So distance moved by it in 0.104 h
distance moved by the boat in upstream direction given as


In y direction the displacement of boat is

net displacement of the ball is given as



To solve this
problem, we should remember that:
Energy = Force x Distance
Since we are talking about charges, therefore we make use
of Coulumb’s law for the electrical force between the two charges:
F = k q1 q2 / d^2
Where,
k = Coulumb’s constant = 9 x 10^9 N m^2/ c^2
q = charge
d = distance between the charges
Plugging back into the energy equation:
E = (k q1 q2 / d^2) * d
E = k q1 q2 / d
Solving for E using the given values:
E = (9 x 10^9 N m^2/ c^2) (3.4 E -6 c) (6.6 E -6 c) /
0.10 m
<span>E = 2.02 N m = 2.02 J</span>
Answer:
A. 12 m/s
Explanation:
Let’s remember that the definition of velocity is the variation of position of an object respect with to time. We know that the boy dropped the stone when the boat was 27 meters from the bridge and the stone hit the water 3 meters in front of the boat. So, the Boat must have traveled x=27 m-3m=24 m. The next step is calculating the amount of time that took the boat to make that travel; coincidentally, it is the same time that takes the stone to reach the water.
The equation that describes the motion of the stone is:
y = y_0 + v_0 * t+1/2 * a * t^2
The boy drops the stone from rest, so we can say that v_0=0. We can fixate the reference line on top of the bridge, so y_0=0 as well. The equation will be then:
-19,6 m = -1/2 * 9,8 m/s^2 * t^2
t^2= -(19,6 m)/(-4,9 m/s^2) = 4,012 s^2
t=√(4,012 s^2) = 2,003 s
Knowing the time that takes the stone to reach the water, that is the same that time that the boat uses to travel the 24 meters. The velocity of the boat is:
v = ∆x/∆t = (27 m-3 m)/(2,003 s-0s) = 11,9816 m/s ≈ 12 m/s
Have a nice day! :D
Answer:

Explanation:
we know angular velocity in terms of moment of inertia and angular speed
ω .... (1)
moment of inertia of rod rotating about its center of length b
........ .(2)
using v = ωr
where w is angular velocity
and r is radius of rod which is equal to b
so we get 2v = ωb
ω = 2v/b ................. (3)
here velocity is two time because two opposite ends are moving opposite with a velocity v so net velocity will be 2v
put second and third equation in ist equation
×
so final answer will be 
<span>The answer should be the vegitation. </span>