A pendulum bob is suspended inside a lift moving upward with constant velocity. If mass of the bob is 50 g then its weight inside the compartment is

Options

A. zero
B. 0.1 N
C. 0.5 N
D. 0.05 N

Explanation

To solve the problem of finding the weight of a pendulum bob suspended inside a lift moving upward with constant velocity, follow these steps:

### Step 1: Understand the situation
The pendulum bob is suspended in a lift that is moving upward with a constant velocity. Since the lift is moving with constant velocity, the acceleration of the lift is zero.

### Step 2: Identify the forces acting on the bob
In this scenario, the forces acting on the bob are:
- The gravitational force (weight) acting downwards, which is given by \( W = mg \).
- The tension \( T \) in the string acting upwards.

### Step 3: Calculate the mass of the bob
The mass of the bob is given as 50 g. To convert this into kilograms (since the standard unit of mass in physics is kg):
\[ \text{Mass} = 50 \, \text{g} = \frac{50}{1000} \, \text{kg} = 0.05 \, \text{kg} \]

### Step 4: Calculate the weight of the bob
The weight of the bob can be calculated using the formula:
\[ W = mg \]
where \( g \) (acceleration due to gravity) is approximately \( 10 \, \text{m/s}^2 \). Substituting the values:
\[ W = 0.05 \, \text{kg} \times 10 \, \text{m/s}^2 = 0.5 \, \text{N} \]

### Step 5: Conclusion
Since the lift is moving with constant velocity, the tension in the string is equal to the weight of the bob. Therefore, the weight of the pendulum bob inside the compartment is:
\[ \text{Weight} = 0.5 \, \text{N} \]

### Final Answer
The weight of the pendulum bob inside the lift is **0.5 N**.

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