Calculating acceleration

The common mistake

Dividing final speed by time without subtracting the starting speed.

Instead: a = (v − u) / t. A negative answer means slowing down.

Worked example with Guide me

A bike goes from 4 m/s to 10 m/s in 3 s. Find its acceleration.

1. Sugar · Change in velocity?
   Student · 10 − 4 = 6 m/s.
2. Sugar · Divide by time.
   Student · 6 ÷ 3 = 2.

Answer: 2 m/s²

Try 3 practice questions

1. 1. 0 to 20 m/s in 5 s?

   Show answer

   4 m/s²

2. 2. 15 m/s to 5 m/s in 2 s?

   Show answer

   −5 m/s²

3. 3. Final speed from 3 m/s with 2 m/s² for 4 s?

   Show answer

   11 m/s

Quick answers

What is the most common mistake with calculating acceleration?

Dividing final speed by time without subtracting the starting speed.

How do I get calculating acceleration right?

a = (v − u) / t. A negative answer means slowing down.

Can you show a worked example?

A bike goes from 4 m/s to 10 m/s in 3 s. Find its acceleration. 2 m/s²

Related concepts

• Speed, distance and time
• Newton's second law (F = ma)
• Mass vs weight