The isotope calcium-41 decays into potassium-41, with a half-life of 1.03 × 105 years. There is a sample of calcium-41 containing 5 × 109 atoms. How many atoms of calcium-41 and potassium-41 will there be after 4.12 × 105 years?

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Explanation:

4.12× 105 years means that those atoms have passed 4 half lives.

In the first half life,

In the second half life,

In the third half life,

In the fourth half life, the remaining Ca-41 atoms will be,

So after 4 half lives, the remaining Ca-41 atoms are 3.125×108. The amount of formed K-41 atoms will be,

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.