1. A compact car with a mass of 875 kg, is traveling at 22 m/s. a. What is the k

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Question

1. A compact car with a mass of 875 kg, is traveling at 22 m/s.

a. What is the kinetic energy of the car?

b. If the same car were traveling at 44 m/s, what would be its kinetic energy?

c. If the car doubled its mass to 1750 kg and traveled at 22 m/s what would be its kinetic energy?

d.. Which has a bigger effect on KE, doubling the mass or doubling the speed?

2. A comet with a mass of 7.85x1011 kg strikes Earth at a speed of 25,000 m/s.

a. Find the kinetic energy of the comet.

b. Compare that energy to the 4.2x1015 J of energy that was released by the largest nuclear weapon ever built, “Tsar Bomba”.

Such a comet collision has been suggested as having caused the extinction of the dinosaurs.

3. A 500 kg boulder sits precariously at the edge of a cliff 50 m tall. What is its potential energy?

v = 22 m/s , m =875 kg

a) Kinetic energy KE = (1/2)mv^2 =(1/2)(875*22*22)

KE = 211750 J

b) v = 44 m/s

KE =(1/2)(875*44*44)

KE = 847000 J

c) m =1750 kg , v =22 m/s

KE = (1/2)(1750*22*22)

KE= 423500 J

(d) Doubling speed have bigger effect on Kinetic energy

2) (a) m =7.85x10^11 kg , v =25000 m/s

KE =(1/2)(7.85x1011)(25000)2

KE = 2.453x1020 J

(b) KE of tsar Bomba = 4.2x10^15 J

K.Ecomet/K.ETsar = 245300/4.2 = 58404

Comet have 58404 times greater kinetic energy than Tsar Bomba.

3) m =500 kg , h =50m , g =9.8 m/s^2

Potentail energy =mgh = 500*9.8*50

= 245000 J

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