Help Solving Kinetic Energy Equation to Find Mass of Car

AI Thread Summary
To find the mass of a car with a kinetic energy of 432,000 Joules traveling at 42 m/s, the equation K.E. = (1/2)(Mass)(Velocity squared) is used. The correct calculation shows that the mass should be significantly larger than 150 kg. Participants suggest that a possible typo or calculation error may have occurred, as one contributor found a mass approximately three times greater. The discussion emphasizes that no unit conversion is necessary since all values are in SI units. Accurate calculations are crucial for determining the correct mass.
drumjunkie
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A car has the kinetic energy of 432000 Joules when traveling at a speed of 42 m/s.

What is its mass? (Kg)

I know that K.E. = (1/2)(Mass)(Velocity squared)

So the equation reads 432000 = (1/2)(42 squared)(M)
I got an answer of 150 but my online program told me it was wrong.

Help?
Do I need to convert units somewhere?
 
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drumjunkie said:
A car has the kinetic energy of 432000 Joules when traveling at a speed of 42 m/s.

What is its mass? (Kg)

I got an answer of 150 but my online program told me it was wrong.

Do I need to convert units somewhere?
No. Everything is in SI units. I think you just made a typo in your calculator.
 
when I did it, I had an answer about 3 times bigger than yours. Perhaps check your math?
 

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