Answer: Option (a) is the correct answer.
Explanation:
The stream that flows during or after the rainfall is called an ephemeral stream. This stream occurs in areas where there is less rainfall or deficiency of moisture.
The stream that flows only in flat lands is called as river.
Mechanical weathering results in the breaking of rocks causes ice wedging.
Chemical weathering results in the change in molecular structure of rocks and soil.
Thus, it can be concluded that option (a) is the correct answer.
The formula of mechanical advantage in this situation is:
MA = Input Force ÷ Output Force
The input force is the 30N applied to a screwdriver while the output force is the 75N force to the lid.
So,
MA = 30N/75N
MA = 0.40
Hence the mechanical advantage of the screwdriver is 0.40.
