Which of the following is/are NOT true about an object on which only one force acts?

i. The object can have a zero acceleration.
ii. The object can have zero velocity.
iii. The object can be at rest.

A. i and ii only
B. i, ii, and iii
C. i only
D. i and iii only



Answer :

Certainly! Let's analyze each statement to determine its truthfulness step by step.

### Given Statements:

[i] The object can have zero acceleration.

- According to Newton's second law of motion, [tex]\( F = m \cdot a \)[/tex], where [tex]\( F \)[/tex] is the force, [tex]\( m \)[/tex] is the mass, and [tex]\( a \)[/tex] is the acceleration.
- If there is a nonzero force acting on an object ([tex]\( F \neq 0 \)[/tex]), and considering [tex]\( m \)[/tex] is never zero, the acceleration [tex]\( a \)[/tex] cannot be zero. Therefore, this statement is NOT true.

[ii] The object can have zero velocity.

- Velocity is the speed of an object in a particular direction, and it can be zero if the object is momentarily at rest or if it starts from rest.
- Even if a force is acting on the object, it can have zero velocity at some instant, such as when the object momentarily stops and then changes direction.
- Therefore, this statement can be true.

[iii] The object can be at rest.

- An object can indeed start from rest before the force begins to act on it.
- There are no conditions in Newton's laws that prevent the object from being at rest initially before the force is applied.
- Therefore, this statement can be true.

### Conclusion:

- Statement [i] is not true based on Newton's second law.
- Statement [ii] can be true, so it doesn't belong to the "NOT true" category.
- Statement [iii] can be true, so it isn't in the "NOT true" category either.

The correct answer is the statement which is NOT true about an object on which only one force acts:

[C] i only

So, the answer is: [tex]\([C] i only\)[/tex]