**Question:**

**Supposing Newton’s law of gravitation for gravitation forces F1 and F2 between two masses m1 and m2 at positions r1 and r2 read **

**$F_{1}=-F_{2}=-\frac{r_{12}}{r_{12}^{3}} G M_{0}^{2}\left(\frac{m_{1} m_{2}}{M_{1}^{2}}\right)^{n} \quad$ where $\mathrm{Mo}$ is a constant of the dimension of mass, $\mathrm{r}_{12}=$**

**r1 – r2 and n is a number. In such a case,**

**(a) the acceleration due to gravity on earth will be different for different object**

**(b) none of the three laws of Kepler will be valid**

**(c) only the third law will become invalid**

**(d) for n negative, an object lighter than water will sink in water**

**Solution:**

The correct answers are

(a) the acceleration due to gravity on earth will be different for different object

(c) only the third law will become invalid

(d) for n negative, an object lighter than water will sink in water