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What is the KE of a 45 kg object moving at 13 m/s?

What is the KE of a 45 kg object moving at 13 m/s?. Given: m = 45 kg v = 13 m/s Unknown: KE Equation: ½ mv 2 (.5 * m * v 2 ) Solve: .5 * 45 kg * (13 m/s) 2 Solution: 3802.5 J. Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.

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What is the KE of a 45 kg object moving at 13 m/s?

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  1. What is the KE of a 45 kg object moving at 13 m/s?

  2. Given: • m = 45 kg • v = 13 m/s • Unknown: KE • Equation: ½ mv2 (.5 * m * v2) • Solve: .5 * 45 kg * (13 m/s) 2 • Solution: 3802.5 J

  3. Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.

  4. If the roller coaster car in the above problem were moving with twice the speed, then what would be its new kinetic energy?  KE = 1/2M*v2= (0.5) * (625 kg) * (18.3 m/s)2KE = 1.05 x105 Joules

  5. If the speed is doubled, then the KE is quadrupled. So, KE = 4 * (1.05 x 105 J) = 4.2 x 105 Joules. -or-KE = 0.5*m*v2KE = 0.5*625 kg*(36.6 m/s)2KE = 4.2 x 105 Joules

  6. Missy Diwater, the former platform diver for the Ringling Brother's Circus, had a kinetic energy of 12 000 J just prior to hitting the bucket of water. If Missy's mass is 40 kg, then what is her speed?

  7. KE = 1/2m*v2Rearrange to solve for v= v = 24.5 m/s

  8. A 900-kg compact car moving at 60 mi/hr has approximately 320 000 Joules of kinetic energy. Estimate its new kinetic energy if it is moving at 30 mi/hr. (HINT: use the kinetic energy equation as a "guide to thinking.")

  9. KE = 80 000 JThe KE is directly related to the square of the speed. If the speed is reduced by a factor of 2 (as in from 60 mi/hr to 30 mi/hr) then the KE will be reduced by a factor of 4. So, the new KE is (320 000 J)/4 or 80 000 J.

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