Acceleration Calculator

The basic formula is a = (v - v0) / t, where a is acceleration, v is final velocity, v0 is initial velocity, and t is time. This gives average acceleration. From Newton's Second Law, a = F/m (force divided by mass). Centripetal acceleration for circular motion is a = v2/r where r is the radius.

Velocity describes how fast an object is moving and in what direction (m/s). Acceleration describes how quickly velocity is changing (m/s2). An object moving at constant velocity has zero acceleration. You can accelerate by changing speed, direction, or both.

Negative acceleration (often called deceleration) means the velocity is decreasing in the positive direction, or increasing in the negative direction. A car braking has negative acceleration. However, negative acceleration doesn't always mean slowing down - an object accelerating backwards (negative direction) from rest has negative acceleration but is speeding up.

Centripetal acceleration is the acceleration directed toward the center of a circular path that keeps an object moving in a circle. The formula is a = v2/r, where v is the tangential velocity and r is the radius. Even at constant speed, there's acceleration because the direction is constantly changing.

G-force measures acceleration relative to Earth's gravitational acceleration (g = 9.81 m/s2). At 1g, you feel your normal weight. At 2g, you feel twice as heavy. Fighter pilots experience up to 9g in tight turns. At 0g (weightlessness), like in orbit, you feel no gravitational pull. Sustained high g-forces can cause blackouts.

Newton's Second Law states F = ma, which can be rearranged to a = F/m. This means acceleration is directly proportional to force and inversely proportional to mass. Doubling the force doubles the acceleration. Doubling the mass halves the acceleration. This explains why heavier objects need more force to accelerate equally.

The SI unit is meters per second squared (m/s2), meaning velocity changes by that many m/s each second. Other units include ft/s2, km/h/s, and g (multiples of Earth's gravity). 1 g = 9.81 m/s2 = 32.2 ft/s2. Acceleration of 10 m/s2 means speed increases by 10 m/s every second.

Earth's gravity: 9.81 m/s2 (1g). Car 0-60 mph in 6s: ~4.5 m/s2. Commercial jet takeoff: ~2.5 m/s2. Sports car braking: ~10 m/s2. Roller coaster: up to 4g. Space shuttle launch: ~3g. Bullet leaving gun: ~100,000 m/s2. Cheetah sprint: ~10 m/s2.