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R.R. Jha
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1. An automobile traveling at 25 km/hour has kinetic energy

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1. An automobile traveling at 25 km/hour has kinetic energy equal to 1 x 10^4 J.
a. What is the mass of the car?
b. If the velocity of the car is increased to 50 km/hour, what is its kinetic energy?
c. If the velocity is increased to 75 km/hour, what is its kinetic energy?
2. A rock with a mass of 1.0 kg, is at the top of a hill and has a potential energy of 50 J.
a. How high is the hill?
b. If the rock rolls to the bottom of the hill, what is its kinetic energy at the bottom of the hill?
3. A certain pendulum has a potential energy of 20 J when it is at the top of its swing.
a. What is the kinetic energy?

b. When the pendulum reaches a certain point in its downward motion it has a potential energy of 5 J. What is its kinetic energy?

c. At the bottom of the swing its potential energy is zero. What is its kinetic energy?
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R.R. Jha and 2 other Homework Specialists are ready to help you
Customer: replied 6 years ago.
On question one B and C, should I go ahead and finish multipling out to get the total for the J? Thank you for explaining this out so I understand it! I am having a terrible time understanding this stuff.
You may do it one way or another. You may do the multiplication the I initially showed, or a smarter way, that is based on squared-velocity relation with kinetic energy, meaning if we make velocity 2-times, like in part b, KE would become 4-times, or if we make velocity 3-times like in part c, KE would become 9 times. Choose what you prefer.
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