Friday, May 3, 2013

What is the kinetic energy of a 30 gram bullet that is traveling at 200 m/s?

Step 1: Identify the formula needed to solve this problem.


The formula for kinetic energy (KE) is:  


KE = 1/2m`~v^2`


m = mass


v = velocity


Step 2: Make a list of the values given in the question.


mass (m) = 30 g


velocity (v) = 200 m/s


Step 3: Make sure all of the given values have the correct unit.


Kinetic energy (KE) is measured in Joules (J). One Joule is the same as 1 `~Kg•m^2/s^2` . Since the mass unit included in the unit for kinetic energy is kilograms (Kg), we need to convert our given mass from grams to kilograms (Kg). We can use the conversion factor 1 Kg = 1000 g to convert between grams and kilograms.


(30 g)(1Kg/1000 g) = 0.03 Kg


Step 4: Plug the given values into the formula and calculate.


KE = `~1/2(0.03)(200)^2` = 600 J

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