A weed trimmer for yard work has a rotating head which consists of a spool of monofilament line, with a strand of line that extends out from the edge. The spool has an inner diameter of 3.00 cm and an outer diameter of 18.0 cm, and a mass of 100 g. The strand has a length of 16.0 cm. The monofilament line has a linear density of 10.0 g/m. -16.0 cm- Need Help? -3.00 cm (a) When switched on, the trimmer speeds up from 0 to 2,500 rev/min in 0.225 s. What average power (in W) is delivered to the head by the trimmer motor while it is accelerating? (Round your answer to at least one decimal place.) W -18.0 cm- (b) When the trimmer is cutting weeds, it spins at 2,100 rev/min and the weeds exert an average tangential force of 9.15 N on the outer end of the line, which is still at a radial distance of 16.0 cm from the outer edge of the spool. What is the power (in W) delivered to the head under load? Read

A weed trimmer for yard work has a rotating head which consists of a spool of monofilament line, with a strand of line that extends out from the edge. The spool has an inner diameter of 3.00 cm and an outer diameter of 18.0 cm, and a mass of 100 g. The strand has a length of 16.0 cm. The monofilament line has a linear density of 10.0 g/m. -16.0 cm- Need Help? -3.00 cm (a) When switched on, the trimmer speeds up from 0 to 2,500 rev/min in 0.225 s. What average power (in W) is delivered to the head by the trimmer motor while it is accelerating? (Round your answer to at least one decimal place.) W -18.0 cm- (b) When the trimmer is cutting weeds, it spins at 2,100 rev/min and the weeds exert an average tangential force of 9.15 N on the outer end of the line, which is still at a radial distance of 16.0 cm from the outer edge of the spool. What is the power (in W) delivered to the head under load? Read

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Description: A weed trimmer for yard work has a rotating head which consists of a spool of monofilament line, with a strand of line that extends out from the edge. The spoolhas an inner diameter of 3.00 cm and an outer diameter of 18.0 cm, and a mass of 100 g. T

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter15: Fluid Mechanics

Section: Chapter Questions

Problem 28P

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Concept explainers

Fluid Pressure

The term fluid pressure is coined as, the measurement of the force per unit area of a given surface of a closed container. It is a branch of physics that helps to study the properties of fluid under various conditions of force.

Gauge Pressure

Pressure is the physical force acting per unit area on a body; the applied force is perpendicular to the surface of the object per unit area. The air around us at sea level exerts a pressure (atmospheric pressure) of about 14.7 psi but this doesn’t seem to bother anyone as the bodily fluids are constantly pushing outwards with the same force but if one swims down into the ocean a few feet below the surface one can notice the difference, there is increased pressure on the eardrum, this is due to an increase in hydrostatic pressure.

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Question

A weed trimmer for yard work has a rotating head which consists of a spool of monofilament line, with a strand of line that extends out from the edge. The spool
has an inner diameter of 3.00 cm and an outer diameter of 18.0 cm, and a mass of 100 g. The strand has a length of 16.0 cm. The monofilament line has a
linear density of 10.0 g/m.
16.0 cm-
Need Help?
3.00 cm
(a) When switched on, the trimmer speeds up from 0 to 2.500 rev/min in 0.225 s. What average power (in W) is delivered to the head by the trimmer motor
while it is accelerating? (Round your answer to at least one decimal place.)
-18.0 cm-
(b) When the trimmer is cutting weeds, it spins at 2,100 rev/min and the weeds exert an average tangential force of 9.15 N on the outer end of the line,
which is still at a radial distance of 16.0 cm from the outer edge of the spool. What is the power (in W) delivered to the head under load?
W
Read

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A 50.0-kg woman wearing high-heeled shoes is invited into a home in which the kitchen has vinyl floor covering. The heel on each shoe is circular and has a radius of 0.500 cm. (a) If the woman balances on one heel, what pressure does she exert on the floor? (b) Should the homeowner be concerned? Explain your answer.
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