# Using symbols to find a answer

## Homework Statement

A car is 12 m from the bottom of a ramp that is 8.0 m long at its base and 6.0 m high. The car moves from rest toward the ramp with an acceleration of magnitude 2.5 m/s2. At some instant after the car begins moving, a crate is released from rest from some position along the ramp. The crate and car reach the bottom of the ramp at the same instant and at the same speed. (a) At what distance d up the ramp was the crate released? (b) How many seconds after the car started was the crate released?

## Homework Equations

x(t) = xi + vx,i * t + 1/2ax2*t2
v(t) = v + at

## The Attempt at a Solution

I know that the final symbol of this is d=(xf*ax)/g*sin(theta) . which comes to be 5.1m for question (a). How does one answer this question through just using symbols, my teacher is not allowing us to plug in numbers on the way, but rather plug in everything in the end. I'm also confused at which equation I should use.

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Dr. Courtney
Gold Member
You need a good diagram to define your coordinate system and symbols.

You also have two moving objects, which means you need to use different equations for the two different objects.

This is an involved problem where you will have more than one equation and more than one step.

Start with a good picture. Think about each object and which equations are needed for its motion.

Then consider which quantity connects the motion of the two objects.

haruspex
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