Explain how forces affect the motion of the planets

Any moving object in space will travel in a straight line at the same speed forever, planets included. The planets would be moving in straight lines, but the sun's gravity pulls them toward it. The force of gravity causes the moving planets to travel in roughly circular orbits around the sun.

The half life of the material approximately 7years

Explanation:

Half life is defined as the time taken by a radioactive material to decay to half of its original substance.

Half life t1/2 = ln2/λ

λ is the decay constant.

To get the decay constant , we will use the relationship

N = Noe^-λt

No is the initial value of the substance

N is the final value of the substance after decay

t is the time taken by the substance to decay.

From the formula

N/No = e^-λt ... (1)

If radioactive nuclei decreases to one-sixteenth the number present initially, this means N = 1/16No

N/No = 1/16

t = 29days

Substituting this values into equation 1 we have:

1/16 = e^-29λ

Taking the ln of both sides

ln(1/16) = lne^-29λ

ln(1/16) = -29λ

λ = ln(1/16)/-29

λ = ln0.0625/-29

λ = -2.77/-29

λ = 0.0955

Substituting λ = 0.0955 into the half life formula, we have;

t1/2 = ln2/0.0955

t1/2 = 7.26days

The half life of the materia is 7.26years