# Homework Help: Basic acceleration question

1. Jun 11, 2007

### hiddenlife5009

1. The problem statement, all variables and given/known data

A cheetah, the fastest of all land animals over a short distance, can accelerate from zero to 18.0 m/s in three strides and to a full speed of 31.3 m/s in seconds. Assuming the first three strides are each 4.1 m long and that acceleration is constant until the cheetah reaches full speed, what is the cheetah's acceleration (in m/s2)?

2. Relevant equations

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3. The attempt at a solution

It is a basic question, but I am over looking something because I cannot figure out which equation I should use. From what I know, I need time to find out what the acceleration is, but no time variable is stated. The question also gives you the stride lengths which just confuses me even more.

2. Jun 11, 2007

### Staff: Mentor

You should write out all the kinematic equations you know. Given the right equation, you won't need the time. But you can find the time by considering the average speed.

3. Jun 11, 2007

### hiddenlife5009

Thanks for the help, I have worked it out now.