Two identical winches lift blocks and at constant speed

PHYSICS · Subjective · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power

Problem

Two identical winches lift blocks

A

and

B

at constant speed. Block

A

of mass

m

is raised to a vertical height

2h

. Block

B

of mass

2m

is raised to height

h

. (i) Obtain expressions for the gravitational potential energies

E_{A}

and

E_{B}

of the two blocks in terms of

m

h

and

g

. (ii) Derive the ratio

\dfrac{E_{B}}{E_{A}}

and state which block stores more energy. (iii) The team wants the two blocks to have equal gravitational potential energy by altering only the height to which block

B

is lifted. Keeping its mass

2m

unchanged, determine the required height (in terms of

h

) so that

E_{B}=E_{A}

. (iv) Using the above results, explain how simultaneous changes in mass and height can be planned to keep gravitational potential energy constant.

Related theory

Gravitational Potential Energy
Gravitation
Conservation of energy; conservative and non-conservative forces
Work, Energy and Power
Potential energy
Conservation of energy
Work and Energy

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