A chocolate bar supplies of energy

PHYSICS · Subjective · CBSE · Physics · Work and Energy · Work and Energy

Problem

A chocolate bar supplies

100\,\text{kcal}

of energy. (i) Convert this energy into joules. (Use

1\,\text{cal}=4.2\,\text{J}

and

1\,\text{kcal}=1000\,\text{cal}

.) (ii) A student pushes a lawn roller with a horizontal force of

75\,\text{N}

through a straight path of

20\,\text{m}

each time the path is covered once. Calculate the mechanical work done in one complete trip. (iii) Assuming that all the energy from the chocolate bar is converted solely into this mechanical work, determine how many complete trips along the path the student must make to expend the entire

100\,\text{kcal}

of energy.

Related theory

Work by Constant Forces
Work
Work, energy and power
Work done by a constant force
Work and Energy

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