Question

Jessie and Jaime complete a 4.0km race. Each has a mass of 68 kg. Jessie runs the race at 15 km/h; Jaime walks it at 5.0 km/h. Use the table below.

Activity	Metabolic power(W) of 68kgindividual
Typing	125
Ballroom dancing	250
Walking at 5 km/h	380
Cycling at 15 km/h	480
Swimming at a fast crawl	800
Running at 15 km/h	1150

A.How much metabolic energy does Jessie use to complete the course?

B.How much metabolic energy does Jaime use to complete the course?

Answer 1

Length of the race = L = 4 km

Mass of Jessie = Mass of Jaime = m = 68 kg

Speed of Jessie's running = V₁ = 15 km/h

Speed of Jaime's walking = V₂ = 5 km/h

Time taken by Jessie to complete the race = T₁

Time taken by Jaime to complete the race = T₂

T₁ = L/V₁

T₁ = 4/15 hours

T₁ = (4/15)x60x60 sec

T₁ = 960 sec

T₂ = L/V₂

T₂ = 4/5 hours

T₂ = (4/5)x60x60 sec

T₂ = 2880 sec

Metabolic power of a 68 kg individual running at 15 km/h = P₁ = 1150 W

Metabolic power of a 68 kg individual walking at 5 km/h = P₂ = 380 W

Metabolic energy used by Jessie to complete the race = E₁

Metabolic energy used by Jaime to complete the race = E₂

E₁ = P₁T₁

E₁ = (1150)(960)

E₁ = 1104000 J

E₂ = P₂T₂

E₂ = (380)(2880)

E₂ = 1094400 J

A) Metabolic energy used by Jessie to complete the course = 1104000 J

B) Metabolic energy used by Jaime to complete the course = 1094400 J