Question
a 15g bullet is fired at 840 m/s into a penullum consisting of a 24kg bag of sand. If the bag rises to a height of 80cm, how much energy is converted into thermal energy in the bag?
Emechanical=Ek + Eg
=1/2mv^2 +mgh
=1/5(0.015)(840) + 0
=5292J
Emechanical =Ek + Eg
=1/2mv^2 + mgh
=0 +(24.015)(9.8)(0.8)
=188.28
Total Emechanical = 188.28-5292
=-5103.72, which is the amount of energy convered into thermal energy.
Emechanical=Ek + Eg
=1/2mv^2 +mgh
=1/5(0.015)(840) + 0
=5292J
Emechanical =Ek + Eg
=1/2mv^2 + mgh
=0 +(24.015)(9.8)(0.8)
=188.28
Total Emechanical = 188.28-5292
=-5103.72, which is the amount of energy convered into thermal energy.
Answers
drwls
Eheat = Ek - Eg
is the formula you should have used.
Eheat is the portion of the original KE that was converted to heat
I do not understand what your "Emechanical" is, and how it could be negative.
What you call "Total Emechanical" may be the energy converted to heat, except for the minus sign.
is the formula you should have used.
Eheat is the portion of the original KE that was converted to heat
I do not understand what your "Emechanical" is, and how it could be negative.
What you call "Total Emechanical" may be the energy converted to heat, except for the minus sign.