Question

what is newtons first law of motion?
an object has zero velocity unless an unbalanced force acts on it.
an object continues to accelerate unless an unbalanced force acts on it.
an object continues to decelerate unless an unbalanced force acts on it.
an object moves at a constant velocity unless an unbalanced force acts on it.
need help? review these concept resources.
read about the concept
rate your confidence to submit your answer. high medium low

Explanation:

Newton's first law of motion states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This means an object moves at a constant velocity (which includes being at rest, \(v = 0\)) unless an unbalanced force acts on it.

• The first option “An object has zero velocity unless an unbalanced force acts on it” is incorrect because an object can be in motion (non - zero velocity) and remain in motion (constant velocity) without an unbalanced force.
• The second option “An object continues to accelerate unless an unbalanced force acts on it” is wrong. According to Newton's first law, without an unbalanced force, there is no acceleration (\(a=\frac{F}{m}\), if \(F = 0\), then \(a=0\)).
• The third option “An object continues to decelerate unless an unbalanced force acts on it” is also incorrect. Deceleration is a form of acceleration (\(a<0\)), and without an unbalanced force (\(F = 0\)), \(a = 0\) (no deceleration).

Answer:

An object moves at a constant velocity unless an unbalanced force acts on it.