An 80-kg man climbs a 6-m ladder in 12 seconds. what is his average power expended?

1 answer:

7 0

If the ladder is vertical, then the work done in ascending equals his increase in potential energy.
For a man of mass (m) climbing height (h), the PE is (mgh), where g is the acceleration due to gravity.

If he does this in time t, his average power (rate of working) is:
mgh / t
= 80 * 9.81 * 6 / 12
= 392.4 W.

If the ladder is not vertical but inclined at an angle the horizontal, the power is mgh sin(a) / t.

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A ball is tossed straight up from the surface of a small, spherical asteroid with no atmosphere. The ball rises to a height equa

alukav5142 [94]

Answer:

d. equal to one-fourth the acceleration at the surface of the asteroid.

Explanation:

The explanation is attached as a picture with this answer

Newton's law of universal gravitation is being used to compare the accelerations at the surface and at the top of the ball's path.

as it can be seen in the explanation that the proportional form of the equation is used because we do not need to necessarily use to final form with "G" for comparison calculations.

As per the given scenario only difference between the two points in the gravitational field is the distance from center of the spherical asteroid, i.e. r.

It is taken 2r for the top is the path. hence we obtain (1/4)g as our answer.