Suppose a body that is acted on by only two forces, is accelerated. For this situation, mark the incorrect statement(s) :

Options

A. The body cannot move with constant speed
B. The velocity can never be zero
C. The sum of two forces cannot be zero
D. The two forces must act in the same line

Explanation

To solve the problem of identifying the incorrect statement regarding a body acted upon by two forces and accelerated, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Forces Acting on the Body**:
- We have a body acted upon by two forces, \( F_1 \) and \( F_2 \).
- The body is accelerating, which implies that there is a net force acting on it.

2. **Net Force Calculation**:
- The net force (\( F_{net} \)) acting on the body can be expressed as:
\[ F_{net} = F_2 - F_1 \]
- Since the body is accelerating, \( F_{net} \) must be greater than zero, which implies \( F_2 > F_1 \).

3. **Acceleration and Velocity**:
- According to Newton's second law, the acceleration (\( a \)) of the body can be given by:
\[ a = \frac{F_{net}}{m} = \frac{F_2 - F_1}{m} \]
- Since the body is accelerating, it cannot be moving at a constant speed. Therefore, the statement that the body can move with constant speed is incorrect.

4. **Velocity Cannot Be Zero**:
- If the body is accelerating, it must have a non-zero velocity at that moment. Therefore, it is correct to say that the velocity cannot be zero while the body is accelerating.

5. **Sum of Forces**:
- If the sum of the two forces acting on the body were zero, the body would not accelerate. Since we know the body is accelerating, the sum of the two forces cannot be zero.

6. **Direction of Forces**:
- The statement that "two forces must act in the same line" is incorrect. Forces can act in different directions and still result in a net force that causes acceleration. For example, if \( F_1 \) acts along the x-axis and \( F_2 \) acts along the y-axis, they can still produce a resultant force that causes acceleration.

### Conclusion:
- The incorrect statement among the options provided is that "two forces must act in the same line."