Given:
The force of attraction is F = 48.1 N
The separation between the charges is

Also, the magnitude of charge q1 = q2 = q.
To find the magnitude of charge.
Explanation:
The magnitude of charge can be calculated by the formula

Here, k is the Coulomb's constant whose value is

On substituting the values, the magnitude of charge will be

Thus, the magnitude of each charge is 9.91 x 10^(-4) micro Coulombs.
there is 1000 grams in 1 kilogram
Divide
80/1000 = 0.08
0.08 kilograms is your answer
hope this helps
Answer:
-1.43 m/s relative to the shore
Explanation:
Total momentum must be conserved before and after the run. Since they were both stationary before, their total speed, and momentum, is 0, so is the total momentum after the run off:
where
are the mass of the swimmer and raft, respectively.
are the velocities of the swimmer and the raft after the run, respectively. We can solve for
So the recoil velocity that the raft would have is -1.43 m/s after the swimmer runs off, relative to the shore
Since U=0,
h=1/2gt^2 (h= ut+1/2gt^2, U=0)
h=1/2*10*4*4
h=80m