i recommend Biography of Malala Yousafzai
I have learned her biography
that really motivated me
Since each time trial is the same the average will be the direct answer, and the formula for velocity is distance divided by time, therefore it will come out to, 1.92307692. Whatever your teacher what the rounding process to be will vary but the straight up answer is there.
efficiency=work output/work input×100
since it exhausts(use up)3000j of heat that's the work input and the 1500j is the work input
efficiency=1500/3000×100
=50%
