The given problem can be exemplified in the following diagram:
Since there is no friction or any other external force, the only force acting in the direction of the movement is the component of the weight of the block, therefore, applying Newton's second law:

Replacing the values:

We may cancel out the mass:

Using the gravity constant as 9.8 meters per square second:

Solving the operations:

Therefore, the acceleration is 6.3 meters per square second.
D.
Always use the right tool to get accurate measurements
The mineral with Mohs hardness would be scratched because the mineral with Mohs 7 hardness is stronger than the Mohs 5 mineral. Eventually, that mineral would turn into dust if you kept rubbing it.
Answer:
C. Atoms
Explanation:
The basic unit of matter and the smallest, indivisible unit of a chemical element. It comprises a nucleus (neutrons + protons) that is surrounded by a cloud of electrons.