Answer:

Explanation:
The tension in a cable is given by:

Where
is the mass density of the cable and v is the speed of the cable's pulse. These values are defined as:

The pulse makes four trips down and back along the cable, so 

Replacing (2) and (3) in (1), we calculate the tension in the cable:

Answer:
The horizontal speed of a projectile is constant for the duration of its flight. This is because, once launched, there are no horizontal forces acting on the projectile (air resistance is usually ignored because it is very small) so horizontally the projectile will travel at a constant speed. For any calculations involving the projectile's horizontal motion, we use
distance=speed×time
d=vt
Answer:
a. the charge on the balloon is -1.602^-15 C
b. the charge on the hair is 1.602^-15 C
c. the force is -2.3*10^-16 N
Explanation:
a. 1 electron has charge of -1.602*10^-19 C
10,000 then has a charge of 10000*-1.602*10^-19 = -1.602^-15 C
b. The charge gained by the balloon is equal in measure but with the opposite sign to the change in the hair
c. From Coulomb's law the force is:
F = k*q1*q2/r²
where k = 9×10^9 N*m²/C², q1 and q2 are the charges, and r is the distance (in meters). Replacing with data:
F = 9×10^9*-1.602^-15*1.602^-15/0.01²
F = -2.3*10^-16 N