You need to know the time as well.
As we know that time period of simple pendulum is given as
T = 2π √L/g
here we know that
T = 3.8 s
now from above equation we know that
T² = 4π² (L/g)
now on rearranging the above equation we will have
L = gT² / 4π²
now plug in all data into it
L = (9.8) (3.8)² / (4) (3.14)²
so the length of the cable must be 3.6 m
Answer: 24.97 kg
Explanation:
The gravitational force between two objects of masses M1, and M2 respectively, and separated by a distance R, is:
F = G*(M1*M2)/R^2
Where G is the gravitational constant:
G = 6.67*10^-11 m^3/(kg*s^2)
In this case, we know that
R = 0.002m
F = 0.0104 N
and that M1 = M2 = M
And we want to find the value of M, then we can replace those values in the equation to get
0.0104 N = (6.67*10^-11 m^3/(kg*s^2))*(M*M)/(0.002m)^2
(0.0104 N)*(0.002m)^2/(6.67*10^-11 m^3/(kg*s^2)) = M^2
623.69 kg^2 = M^2
√(623.69 kg^2) = M = 24.97 kg
This means that the mass of each object is 24.97 kg
