- #1

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## Homework Statement

A man runs at a speed of 4.0 m/s to catch a standing bus. When his distance to the door is 6.0m, the bus starts moving forward and continues with a constant acceleration of 1.2 m/s2.

## Homework Equations

a) How many seconds does it take for the man to reach the door ?

b) If at the beginning he is 10.0 m from the door, will he (running at the same speed) ever catch up? Simple answer is not enough - explanatory answer using calculations or graphical method is needed

## The Attempt at a Solution

a)

x

_{m}= 4*t + 6

x

_{b}=1/2*1.2*t

^{2}

x

_{m}= x

_{b}

0.6*t

^{2}+-4t-6=0

delta=30.4

t1= -1.26s (rejected because it's <0)

t1= 7.92s (accepted because it's >0)