Significant digits including only one zero

[alingy1]

Homework Statement

The problem asks us to find deceleration from 60km/h to 0km/h in 1,2 seconds.

Homework Equations

The speed formulas

The Attempt at a Solution

I know how to apply the formula. However, in the problem, it is written 0km/h. How many significant digits is that? How many significant digits should i have in this problem for the final result?

 

[mell0r]

You should have 2 in your answer as acceleration is the change in velocity (i.e. 60km/h in this case). The 0km/h can be ignored in the case of significant digits

 

[alingy1]

Thank you

Thanks that's what I wanted to know. The zero is confusing. Also, for my lab report, I have to jot down the speed of a small toy according to the time passed. At the beginning, the toy is not moving. Should I put 0m/s or the number of significant digits put for the other data, since we can't really be sure the toy is not moving very very slightly?
Thanks again.

 

[mell0r]

If it's not moving initially, 0 m/s will be fine.

 

[lewando]

"Not moving" implies zero km/h with extreme precision. That is different from 0km/h. What would your answer be if the original question was looking for 60km/h to 1km/h?