Mathhelp346
PLEASE HELP:
An automobile accelerates at 1.77 m/s^2 over 6.00s to reach the freeway speed at the end of an entrance ramp. If the car's final speed is 88.0 km/h, what was its initial speed when it began accelerating? Express your answer in kilometers per hour.
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micahwood50
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\[a = \frac{\Delta v}{t} = \frac{v_f - v_o}{t}\]
micahwood50
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Use this formula.
Mathhelp346
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i know the formula im just having trouble converting the units
micahwood50
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Alright, let convert 88 km/h to m/s. \[\frac{ 88 \text{km} }{ \text{h} }\cdot\frac{ 1000 \text{m}}{ \text{km} }\cdot\frac{ 1 \text{h} }{ 3600\text{s} } = ?\]
micahwood50
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|dw:1349065649701:dw|
micahwood50
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Does this clear everything?
Mathhelp346
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24.4
Mathhelp346
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yea
micahwood50
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Yeah, now find Vo
Then convert it back to km/h
Mathhelp346
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so is it 13.78?
Mathhelp346
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km/h
micahwood50
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13.78
Is it in m/s ?
Mathhelp346
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oops yes
Mathhelp346
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how would i convert it back
micahwood50
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Let me show you. |dw:1349067937197:dw|
micahwood50
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|dw:1349068014177:dw|
micahwood50
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\[\frac{13.78 \cdot 3600 \text{km}}{1000 \text{h}}\]
micahwood50
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Just treat units as "variable." You know what I mean?
Mathhelp346
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ok
Mathhelp346
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so it would be 49.6 km/h
micahwood50
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That's correct.
Mathhelp346
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ok ty