A number of discs, each of momentum M kg m/s ar striking a wall at the rate of n discs per minute. The force associates with these discs, in newotns, would be

Options

A. `(Mn)/60`
B. `60Mn`
C. `M/(60n)`
D. `n/(60M)`

Answer

To find the force associated with the discs striking the wall, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Problem**:
We have discs each with momentum \( M \) (in kg m/s) striking a wall at a rate of \( n \) discs per minute. We need to calculate the force exerted by these discs on the wall.

2. **Using the Concept of Force**:
According to Newton's second law, force (\( F \)) is the rate of change of momentum (\( \frac{dp}{dt} \)). Therefore, we can express the force as:
\[ F = \frac{dp}{dt} \]

3. **Calculating the Change in Momentum**:
Each disc has a momentum \( M \). If \( n \) discs strike the wall per minute, the total momentum change per minute is:
\[ \text{Total momentum change} = n \times M \]

4. **Converting Time Units**:
Since the rate \( n \) is given per minute, we need to convert this rate into seconds. There are 60 seconds in a minute, so:
\[ dt = \frac{1}{60} \text{ minutes} = 1 \text{ minute} = 60 \text{ seconds} \]

5. **Calculating the Rate of Change of Momentum**:
The rate of change of momentum per second (\( \frac{dp}{dt} \)) can be calculated as:
\[ \frac{dp}{dt} = \frac{n \times M}{60} \]

6. **Final Expression for Force**:
Substituting this into the force equation gives:
\[ F = \frac{n \times M}{60} \]

Thus, the force associated with the discs striking the wall is:
\[ F = \frac{nM}{60} \text{ Newtons} \]

### Final Answer:
The force associated with these discs, in Newtons, would be \( \frac{nM}{60} \).