Answer:
20 seconds
Explanation:
The equation for Power is:

Which means...

We can plug in the given values into the equation:


So first Identify all the given Varibales so u can choose which Eqauton to use
D=200m
T=4s
Vi=10m/s
Vf=?
You should this equation
D= 0.50(Vf+Vi)T
Plug in the values
200= 0.50 (Vf+10) 4
Divide the 4 out of the right side and if you do sumthing to one side you gotta do it to the other
200 divided by 4= 0.50(Vf+10)
50= 0.50(Vf+10)
Now expand the 0.50
So 50= 0.5Vf + 5 (because 0.5 times 10 is 5)
Now get rid of the 5
50-5= 0.5Vf
45 =0.5Vf now Divide the 0.5 out
45 divided by 0.5 = Vf
And 45/0.5 is 90
So 90=Vf
Therefore the final Velocity is 90m/s
Incomplete question as we have not told to find what.So the complete question is here
A vessel at rest at the origin of an xy coordinate system explodes into three pieces. Just after the explosion, one piece, of mass m, moves with velocity (-60 m/s)i and a second piece, also of mass m, moves with velocity (-60 m/s)j. The third piece has mass 3m.Just after the explosion, what are the (a) magnitude and (b) direction of the velocity of the third piece?
Answer:

Explanation:
Given data
The vessel at rest
Piece one,of mass m,moves with velocity=(-60 m/s)i
Piece two,of mass m,moves with velocity=(-60 m/s)j
Piece three,of mass 3m
As the linear momentum is conserved in this system,Because the system is closed and no external force acting on it
So momentum is given as

As the vessel at rest so the initial momentum is zero
So
