an object will accelerate when

An object will accelerate when its velocity changes, meaning whenever its speed, its direction of motion, or both change.

What “accelerate” really means

• In physics, acceleration is the rate at which velocity changes over time.

• Because velocity has both size (speed) and direction, any change in speed or any turning counts as acceleration.

Situations when an object accelerates

• When its speed increases, like a car pressing the gas pedal to go from 20 km/h to 40 km/h.

• When its speed decreases, such as braking to a stop; this is still acceleration, just opposite the motion (often called deceleration in everyday language).

• When its direction changes at constant speed, like moving around a circular track at steady speed.

Role of forces (why acceleration happens)

• An object accelerates when there is a net (unbalanced) force acting on it; if all forces cancel, it keeps moving at constant velocity.

• Newton’s second law summarizes this as acceleration being proportional to net force and inversely proportional to mass, so heavier objects need more force to accelerate the same amount.

Simple rule to remember

• If nothing about an object’s speed or direction is changing, it is not accelerating.

• The moment either speed or direction changes (even slightly), the object is accelerating.

Information gathered from public forums or data available on the internet and portrayed here.