Anna on left, Bianca on right Anna, 700 N in weight, and Bianca, 500 N in weight

Question

Anna on left, Bianca on right

Anna, 700 N in weight, and Bianca, 500 N in weight, race up a 30 m high hill.

Both start from rest at the same height and stop at the top. Anna chooses the steep path, which is 60 m long. It takes her 40 s to reach the top. Bianca chooses the easier path, which is 100 m long. It takes her 30 s to reach the top.

a) Is the work that Anna does going up the hill

(i) greater than,            (ii) less than,             or (iii) the same as

the work done by Bianca? Explain your reasoning.

b) Is the power generated by Anna in going up the hill

(i) greater than,            (ii) less than,             or (iii) the same as

the power generated by Bianca? Explain your reasoning.

Explanation / Answer

part a:

work energy principle states that, when energy is conserved,

initial energy+work done=final energy

as they climb upto same height and start from same height, difference in potential energy is same.

hence work done is same .

so option iii is the correct answer.

part b:

power =energy/time

as energy generated is same but time taken is higher for anna, power generated by anna is lesser than power generated by Bianca.

hence option ii is correct.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.