Am I correct?? If not please provide detail. a.) Speed at point B E Tot = KE + U

Question

Am I correct?? If not please provide detail.

a.)

Speed at point B

ETot = KE + U

KE = (1/2) m v2

U = m g h

ETot, A = 0 + (5 kg)(9.8 m/s2)(5 m) = 245 J

ETot = 245 J = constant

ETot, B = (1/2)(5 kg)(vB2) + (5 kg)(9.8 m/s2)(3.2 m) = ETot = 245 J

(1/2)(5 kg)(vB2) + 156.8 J = 245 J

(1/2)(5 kg)(vB2) = 245 J - 156.8 J = 88.2 J

vB2 = (35.38)(J/kg)

vB2 = (35.38)(m2/s2)

vB = 5.9 m/s

speed at point C

ETot, C = (1/2)(5 kg)(vC2) + (5 kg)(9.8 m/s2)(2.0 m) = ETot = 245 J

(1/2)(5 kg)(vC2) + 98 J = 245 J

(1/2)(5 kg)(vC2) = 245 J - 98 J =147 J

vC2 = 147 J / 2.5 kg

vC2 = (147/2.5)(J/kg)

vC2 = (58.8)(J/kg)

vC = 7.7 m/s

b.)

WAC = m g h

WAC = (5 kg) ( 9.8 m/s2) (5.0 m - 2.0 m)

WAC = (5 kg) ( 9.8 m/s2) (3.0 m)

WAC = 147 J

Explanation / Answer

Looks good to me.

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