Question

a student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec. a student has gone a vertical distance of 8.0m. determine the amount of work done by the student to elevate his body to this height . assume that his speed is constant​

Answer 1

Explanation:

The student weighs 784 N (Fgrav= 80 kg * 9.8 m/s/s).

To lift a 784-Newton person at constant speed, 784 N of force must be applied to it (Newton's laws). The force is up, the displacement is up, and so the angle theta in the work equation is 0 degrees. Thus,

W = (784 N) * (8 m) * cos (0 degrees) = 6272 Joules

Answer 2

Answer:

The amount of work done by the student to elevate his body to this height is 6278.4 J.

Explanation:

Given:

Student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec.

Student has gone a vertical distance of 8.0 m.

To Find:

The amount of work done by the student to elevate his body to this height.

Formula Used:

Work = Force x Displacement

Force = Weight of student

Weight = Mass x Acceleration due to gravity

Solution:

As given,student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec.

Mass, m = 80 kg

Acceleration due to gravity, g = 9.81 m/s²

Weight $= 80 \times 9.81 = 784.8 N$

As given,student has gone a vertical distance of 8.0 m.

Displacement = 8 m

Work $= 784.8 \times 8 = 6278.4 J$

Therefore,the amount of work done by the student to elevate his body to this height is 6278.4 J.

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