The carbon dating method discussed in the video is useful for determining the ages of living materials that are a few thousand or a few tens of thousands years old. K-40 decays into Ar-40 with a half life of 1.2 billion years, making it suitable for estimating the age of very old astronomical objects (for the simplicity of this problem, we assume that this is the only possible decay for K-40). Assume that when a particular rock formed, it had a decay rate of 0.061 decays/sec/g, and it now has a decay rate of 0.015 decays/sec/g. Using the estimation method in the video, which is the closest estimate for the age of this rock? a. 0.3 billion years
b. 0.6 billion years
c. 1.2 billion years
d. 2.4 billion years
e. 4.8 billion years

Answer: a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same sign as the  -4.0  µc charge.======electricstatic force between two point charges  is given by    where k is coulomb's constant,  8.99×10⁹  n·m²/c², q₁ and q₂ are the point charges, and r is the distance between the two point charges.assign positive to q₁let q₁ =  6.0 µc, q₂ = -4.0  µc, q₀ represent the charge at the origin, and q₃ represent this new charge to place.the charge at the origin q₀ would experience the following force f₀₁ from q₁, with r = 6.0 m (note that 1  µc = 10⁻⁶ c)    the force from q₂    the force from q₃    the net force on the origin charge, q₀, has to be zero for no electrostatic forcehaving an equation where k and q₀ can be divided out of the equation will allow us to solve for q₃    isolating:     a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same as the  -4.0  µc charge