Question

Calculate the power transmitted by a V-belt in kW, if the speed of belt=10 m/s, tension in the tight side of the belt=100 N, tension in the slack side of belt=70 N

• A. 0.1 kW
• B. 0.2 kW
• C. 0.3 kW
• D. 3.0 kW

Hint:

Power (Watts) = Effective Pull (N) $\times$ Speed (m/s). Dividing by 1000 gives kW directly: $\frac{(100 - 70) \times 10}{1000} = 0.3\text{ kW}$.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The power transmitted by a flexible belt drive depends directly on the net effective tension (difference between tight side tension and slack side tension) and the linear belt velocity.
Key Formula or Approach:
\[ P = (T_1 - T_2) \cdot v \]
where \(T_1\) is tight side tension (N), \(T_2\) is slack side tension (N), and \(v\) is belt speed (m/s).

Step 2: Detailed Explanation:
Given parameters:
- Tight side tension: \(T_1 = 100\text{ N}\)
- Slack side tension: \(T_2 = 70\text{ N}\)
- Linear belt speed: \(v = 10\text{ m/s}\)
Effective driving tension:
\[ T_e = T_1 - T_2 = 100\text{ N} - 70\text{ N} = 30\text{ N} \]
Power transmitted in Watts:
\[ P = T_e \times v = 30\text{ N} \times 10\text{ m/s} = 300\text{ W} \]
Converting to kilowatts (kW):
\[ P = \frac{300}{1000} = 0.3\text{ kW} \]

Step 3: Final Answer:
Therefore, the power transmitted is 0.3 kW, matching option (C).