एक 5 kg द्रव्यमान वाली वस्तु पर 2s के लिये एक नियत बल कार्यरत होता है। यह वस्तु के वेग को 3m/s से बढा 7m/s कर देता है। लगाये गये बल की मात्रा ज्ञात करें

Options

A. a. 5 N
B. b. 10 N
C. c. 15 N
D. d. 20 N

Answer

To solve the problem, we need to find the force applied to a 5 kg object that increases its velocity from 3 m/s to 7 m/s over a period of 2 seconds. We can use Newton's second law of motion and the concept of acceleration.

### Step-by-Step Solution:

1. **Identify the given values:**
- Mass of the object (m) = 5 kg
- Initial velocity (u) = 3 m/s
- Final velocity (v) = 7 m/s
- Time (t) = 2 s

2. **Calculate the change in velocity (Δv):**
\[ \Delta v = v - u = 7 \, \text{m/s} - 3 \, \text{m/s} = 4 \, \text{m/s} \]

3. **Calculate the acceleration (a) using the formula:**
\[ a = \frac{\Delta v}{t} = \frac{4 \, \text{m/s}}{2 \, \text{s}} = 2 \, \text{m/s}^2 \]

4. **Apply Newton's second law to find the force (F):**
\[ F = m \cdot a \]
Substituting the values:
\[ F = 5 \, \text{kg} \cdot 2 \, \text{m/s}^2 = 10 \, \text{N} \]

5. **Conclusion:**
The magnitude of the force applied is **10 Newtons**.