Question #25365

How do i do this question. A weightlifter lifts a 32 kg set of weights from ground level to position over the head. The vertical lift is 2.2 m. How much work does the weightlifter do

Expert's answer

Let's write the law conservation of energy(the work which the weightlifter do will equal to difference between initial and final potential energies):

A = U2 - U1

A - work which the weightlifter do,

U1, U2 - initial and final potential energies

U = mgh - the definition of the potential energy

m - mass

g - gravitational acceleration

h - high

At the beginning, the weightlifter was staying on the ground, so h=0.

A = mgh - mg*0 = mgh

A = 32*2.2*9.8 = 689.92 J

Answer: 689.92 J

A = U2 - U1

A - work which the weightlifter do,

U1, U2 - initial and final potential energies

U = mgh - the definition of the potential energy

m - mass

g - gravitational acceleration

h - high

At the beginning, the weightlifter was staying on the ground, so h=0.

A = mgh - mg*0 = mgh

A = 32*2.2*9.8 = 689.92 J

Answer: 689.92 J

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