A body of mass 40 gm is moving with a constant velocity of `2cm//sec` on a horizontal frictionless table. The force on the table is

Options

A. Zero
B. 39200
C. 160
D. 80

Explanation

To solve the problem step by step, we need to determine the force acting on the body on a horizontal frictionless table.

### Step 1: Understand the given information
- Mass of the body (m) = 40 grams
- Velocity (v) = 2 cm/s
- The surface is frictionless.

### Step 2: Identify the forces acting on the body
Since the body is moving on a horizontal frictionless table, the only forces acting on it are:
1. The gravitational force (weight) acting downwards, which is given by \( F_g = mg \).
2. The normal force exerted by the table acting upwards.

### Step 3: Calculate the gravitational force
To find the gravitational force, we need to use the formula:
\[ F_g = m \cdot g \]
Where:
- \( m = 40 \) grams = \( 0.04 \) kg (since 1 gram = 0.001 kg, but we will keep it in grams for CGS unit)
- \( g \) (acceleration due to gravity) in CGS units = \( 980 \) cm/s²

Now, substituting the values:
\[ F_g = 40 \, \text{g} \cdot 980 \, \text{cm/s}^2 \]

### Step 4: Perform the calculation
Calculating the force:
\[ F_g = 40 \cdot 980 = 39200 \, \text{dynes} \]

### Step 5: Conclusion
Since the body is moving with constant velocity, the net force acting on it in the horizontal direction is zero. However, the force acting on the table due to the body is equal to the weight of the body, which we calculated as \( 39200 \, \text{dynes} \).

Thus, the force on the table is **39200 dynes**.

### Final Answer:
The force on the table is **39200 dynes**.

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