Answer :

Mass of the athlete = m = 50 kg

It is given to assume that she travelled the 100 m distance in 10.54 s with a uniform speed, v


v = 100/10.54 = 9.48766603 ≈ 9.4877 m/s


(a.) Kinetic energy of Griffith-Joyner at this speed = mv2/2


= 50×9.4877×9.4877×0.5


= 2250.411 ≈ 2250 J


(b.) Force of resistance F = weight of the athlete / 10


= 50 × 9.8 × 0.1


= 49 N


Since, speed is assumed to be a constant, acceleration a =0 m/s2


Force in the direction of motion or acceleration = ma = 0


Total work done by resistance = Fscosθ


(where θ = angle between resistant force F and displacement s)


= 49 × 100 × cos 180°


= -4900 J


(c.) Power = work done / time for which the work is done


= 4900/10.54


= 464.89 J/s or W


≈ 465 W


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses
RELATED QUESTIONS :

A body is moving Physics - Exemplar

The average work Physics - Exemplar

A person trying tNCERT - Physics Part-I

An unruly demonstHC Verma - Concepts of Physics Part 1

The 200 m free stHC Verma - Concepts of Physics Part 1

A scooter companyHC Verma - Concepts of Physics Part 1

A pump on the groNCERT - Physics Part-I

A family uses 8 kNCERT - Physics Part-I