# A car travelling at 50km/h stops in 70.0m…HELP

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

A car travelling at 50.0 km/h stops in 70.0 m. What is the stopping distance if the car’s speed is 90 km/h?

**2. Relevant equations**

This is a question in the unit about momentum & energy, so most of the questions have been applying formulae about momentum, work, gravitational potential energy, kinetic energy, etc. I’m confused as to how this question relates to this section because I can’t seem to find an applicable formula.

**3. The attempt at a solution**

I attempted to solve this using ratios and got an answer of 126 m, but the real answer is somewhere around 2.3E2 m. I’m super confused, but expecting that it’ll be a super obvious solution…?

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