During a school science exhibition

PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy

Problem

During a school science exhibition, a miniature lift model powered by a small motor must raise a

20\,\text{kg}

platform vertically through a height of

6\,\text{m}

. The motor output is not constant: • First

3\,\text{m}

: steady output of

120\,\text{W}

• Next

3\,\text{m}

: steady output of

180\,\text{W}

Take

g = 10\,\text{m/s}^2

. (a) Calculate the total mechanical work done in raising the platform through

6\,\text{m}

. (b) Determine the time taken during the first

3\,\text{m}

segment. (c) Determine the time taken during the second

3\,\text{m}

segment. (d) Find the total time for the complete lifting cycle.