1) A shot-putter accelerates a 7.12 kg shot from rest to 14.4 m/s. If this motio

Question

1) A shot-putter accelerates a 7.12 kg shot from rest to 14.4 m/s. If this motion takes 1.86 s, what average power was developed?

2) In the rope climb, a 72.8 kg athlete climbs a vertical distance of 4.72 m in 9.12 s. What minimum power output was used to accomplish this feat?

3) Calculate the power output of a 75.3 kg athlete who accelerates from rest to a speed of 8.33 m/s in a time of 4.35 s.

4) A person shoveling snow from a sidewalk is metabolizing food at a rate of 930 W.

calculate the power output during this activity.

B)How long will it take for this person to lift 3500 kg of snow to a height of 1.2m ?

Explanation / Answer

Number 1)

First Find a

vf = vo + at

14.4 = 0 + a(1.86)

a = 7.74 m/s^2

F = ma = (7.12)(7.74) = 55.1 N

The distance traveled during the applied force is

d = vot + .5at^2

d = 0 + (.5)(7.74)(1.86)^2

d = 13.4 m

Finally P = Fd/t

P = (55.1)(13.4)/(1.86)

P = 397 W

Number 2)

P = Fd/t

P = (72.8)(9.8)(4.72)/(9.12)

P = 369 W

Number 3)

First Find a

vf = vo + at

8.33 = 0 + a(4.35)

a = 1.91 m/s^2

F = ma = (75.3)(1.91) = 144.2 N

The distance traveled during the applied force is

d = vot + .5at^2

d = 0 + (.5)(1.91)(4.35)^2

d = 18.1 m

Finally P = Fd/t

P = (144.2)(18.1)/(4.35)

P = 600 W

Number 4)

Power = 930 W

P = Fd/t

930 = (3500)(9.8)(1.2)/t

t = 44.3 sec

P = E/t

E = Pt

E = (930)(44.3)

E = 41160 J

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

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