Answer:
-47.04
Explanation:
Divide 12 m by 2.5 m/s which equals 4.8s
And then use 4.8s to multiply it with -9.8
4.8(-9.8)= -47.04 m/s
Hope this helped!! :)
The guys before me was almost right. But instead of it being vertical it is horizontal.
Answer:

Explanation:
T = Tension on the string
E = Electric field
= Permittivity of free space = 
As the forces balance themselves we have the equations


Dividing the equations we get

Electric field is given by

The magnitude of the charge on each plate is 
Step 1: Define an equation that relates the volume of a sphere to its radius.
V = 4/3*π*r3
Step 2: Take the derivative of each side with respect to time (we will define time as "t").
(d/dt)V = (d/dt)(4/3*π*r3)
dV/dt = 4πr2*dr/dt
Step 3: We are told in the problem statement that diameter is 100m, so therefore r = 50mm. We are also told the radius of the sphere is increasing at a rate of 2mm/s, so therefore dr/dt = 2mm/s. We are looking for how fast the volume of the sphere is increasing, or dV/dt.
dV/dt = 4π(50mm)2*(2mm/s)
dV/dt = 62,832 mm3/s