The work done by a motor on a trolley changes with time as described below: • From to

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

The work done by a motor on a trolley changes with time as described below: • From

t = 0\,\text{s}

t = 4\,\text{s}

, the work increases uniformly from

0\,\text{J}

40\,\text{J}

. • From

t = 4\,\text{s}

t = 7\,\text{s}

, the work remains constant at

40\,\text{J}

. • From

t = 7\,\text{s}

t = 9\,\text{s}

, the work decreases uniformly to

22\,\text{J}

. Using this information, answer the following. (i) Calculate the power developed during the first

4\,\text{s}

. (ii) Find the power during the interval from

t = 4\,\text{s}

t = 7\,\text{s}

. (iii) Determine the power during the last

2\,\text{s}

. (iv) Compute the average power for the entire period from

t = 0\,\text{s}

t = 9\,\text{s}