A force of 6N acts on a body at rest and of mass 1kg. During this time, the body attains a velocity of `30 m//s`. The time for which the force acts on body is `:`

Options

A. 7 second
B. 5 second
C. 10 second
D. 8 secons

Answer

To solve the problem, we need to determine the time for which a force of 6 N acts on a body of mass 1 kg, which starts from rest and attains a velocity of 30 m/s.

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Force (F) = 6 N
- Mass (m) = 1 kg
- Initial Velocity (u) = 0 m/s (since the body is at rest)
- Final Velocity (v) = 30 m/s

2. **Use Newton's Second Law:**
According to Newton's second law, the force acting on an object is equal to the mass of the object multiplied by its acceleration (a):
\[ F = m \cdot a \]
Rearranging this gives us:
\[ a = \frac{F}{m} \]

3. **Calculate the Acceleration:**
Substitute the known values into the equation:
\[ a = \frac{6 \, \text{N}}{1 \, \text{kg}} = 6 \, \text{m/s}^2 \]

4. **Use the Equation of Motion:**
We can use the equation of motion that relates initial velocity, final velocity, acceleration, and time:
\[ v = u + a \cdot t \]
Rearranging this to solve for time (t):
\[ t = \frac{v - u}{a} \]

5. **Substitute the Known Values:**
Substitute the values of v, u, and a into the equation:
\[ t = \frac{30 \, \text{m/s} - 0 \, \text{m/s}}{6 \, \text{m/s}^2} = \frac{30}{6} = 5 \, \text{s} \]

6. **Conclusion:**
The time for which the force acts on the body is \( t = 5 \) seconds.

### Final Answer:
The time for which the force acts on the body is **5 seconds**.

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