Question

A sphere of metal has a radius of 4.7 cm and a density of 9.39g/cm^3. What is the mass of the sphere? Answer in units of g

Answer 1

We know the radius of the sphere of metal (it is $r = 4.7 \, \text{cm}$), so, we can find its volume (if we take that $\pi = 3.14$):

$$V = \frac{4}{3} \cdot \pi \cdot r^3 = \frac{4}{3} \cdot \pi \cdot (4.7)^3 = \frac{415.292}{3} \cdot \pi \approx 434.672 \, \text{cm}^3.$$

And we know that a density is $\rho = 9.39 \frac{g}{cm^3}$. So, we can find the mass of the sphere of metal:

$$m = V \cdot \rho = \frac{415.292}{3} \cdot \pi \cdot 9.39 \approx 4081.573 \, g.$$

**Answer:** 4081.573 g.