A cheetah can accelerate from rest to a speed of 30.0 metres per second in 7.00 seconds. What is its acceleration?
Let’s call the acceleration of the cheetah 𝑎. And as we begin, let’s recall the relationship between acceleration, speed, and time. The acceleration 𝑎 of an object is defined as its change in velocity Δ𝑣 divided by its change in time Δ𝑡.
Applying this definition to our scenario, the cheetah speeds up from rest to a speed of 30.0 metres per second. So Δ𝑣 is equal to 30.0 metres per second minus zero metres per second or simply 30.0 metres per second. Δ𝑡 in the denominator we’re told is 7.00 seconds — the time it takes the cheetah to accelerate from rest to 30.0 metres per second.
Before we perform this division to solve for 𝑎, notice that the units we’ll find at the end are metres per second squared. When we calculate this result, we find an acceleration of 4.29 meters per second squared. This is the value of the cheetah’s acceleration.