Question

which statement is true because of newtons second law?
when the net force on an object decreases, the objects acceleration increases.
when the net force on an object decreases, the objects acceleration decreases.
when the net force on an object decreases, the acceleration doesnt change.
when the net force on an object increases, the objects acceleration decreases.

Explanation:

Newton's second law is given by \( F = ma \) (or \( a=\frac{F}{m} \)), where \( F \) is net force, \( m \) is mass, and \( a \) is acceleration. Mass of an object is constant (assuming non - relativistic and non - changing mass scenarios). So, acceleration \( a \) is directly proportional to net force \( F \) (since \( a=\frac{F}{m} \) and \( m \) is constant). If net force \( F \) decreases, and mass \( m \) remains the same, then acceleration \( a \) must also decrease. Let's analyze each option:

• Option 1: If net force decreases, acceleration should decrease (not increase) as they are directly proportional. So this is wrong.
• Option 2: Since \( a=\frac{F}{m} \) and \( m \) is constant, a decrease in \( F \) leads to a decrease in \( a \). This is correct.
• Option 3: Acceleration is directly proportional to net force, so it should change when net force changes. This is wrong.
• Option 4: If net force increases, acceleration should increase (not decrease) as they are directly proportional. This is wrong.

Answer:

B. When the net force on an object decreases, the object's acceleration decreases.