Answer:
1. 
2. 
Explanation:
Hello,
1. In this case, since the volume of the rock is obtained via the difference between the volume of the cylinder with the water and the rock and the volume of the cylinder with the water only:

Thus, the density turns out:

2. In this case, given the density and mass of aluminum we can compute its volume as follows:

Moreover, as the volume is also defined in terms of width, height and length:

The height is computed to be:

Best regards.
Gas pump is the main reason 177m 192 k
B. They work against a strong gravitational force