Notes_Kinetic_Energy_Potential_Energy_2012_KEY

Sample problems a 2 kg car moving with a speed of 2

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Sample Problems A 2 kg car moving with a speed of 2 m/sec starts up a hill. How high does the car roll before it stops? KE in the beginning = PE at the end E k = E p ½ mv 2 = mgh ½ (2) kg x (2 m/s) 2 = 2 kg x 10 m/s 2 x ??? 4 Joules = 20 x ??? Height = 0.2 meters
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8 | P a g e Class Work 1. Theresa’s 5.45 kg dog, Mr. Muggles is napping on top of 2 meter high couch. What is the potential energy of Mr. Muggles? Looking For Given Relationship Solution Potential energy m=5.45 kg h=2m g=10 m/s 2 PE=mgh 109 Joules 2. Garfield (mass = 10.5 kg) is sleeping on top of the 3 meter high couch. What is Garfield’s potential energy? Looking For Given Relationship Solution Potential energy m=10.5 kg h=3 m g=10 m/s 2 PE=mgh 315 Joules 3. A 200 kg pig is standing on top of a 40 meter high muddy hill. What is the pig’s potential energy? Looking For Given Relationship Solution Potential energy m=200 kg h=40 m g=10 m/s 2 PE=mgh 80,000 Joules 4. Tyler (mass=50-kg) is riding in a go-kart down maple avenue. a. What is Tyler’s kinetic energy if he travels at 2 m/s? Looking For Given Relationship Solution Kinetic energy m=50 kg v= 2 m/s KE=1/2 mv 2 100 Joules b. What is Tyler’s kinetic energy if he travels at 4 m/s? Looking For Given Relationship Solution Kinetic energy m=50 kg v= 4 m/s KE=1/2 mv 2 400 Joules
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