Rubbing your hands together warms them by converting work...

Name: Problem 5, Chapter 14: College Physics for AP® Courses
Uploaded: 2019-09-22T01:19:37-08:00
Duration: 3 min 17 s
Channel: Charles Magnusen
Description: Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 20 rubs, at a distance of 7.50 cm per rub, and with an average frictional force of 40.0 N, what is the temperature increase? The mass of tissues warmed is only 0.100 kg, mostly in the palms and fingers.

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 20 rubs, at a distance of 7.50 cm per rub, and with an average frictional force of 40.0 N, what is the temperature increase? The mass of tissues warmed is only 0.100 kg, mostly in the palms and fingers.

Key Concepts

Specific Heat Capacity

Specific heat capacity is a property of a material that indicates how much energy is needed to raise the temperature of one unit of mass by one degree Celsius. It allows the calculation of temperature change when a known amount of heat energy is added or removed, making it a critical concept in understanding how energy affects temperature in materials.

Work

Work is the product of a force applied over a distance. In physics, it represents the energy transferred by a force acting through a displacement. The work done in this context is calculated by multiplying the frictional force by the distance over which it is applied, highlighting the fundamental relationship between force, distance, and energy transfer.

Friction

Friction is the resistive force that occurs when two surfaces move against each other. It converts mechanical energy into thermal energy, often heating the surfaces involved. In scenarios like rubbing hands together, friction is responsible for the generation of thermal energy from the work performed.

Energy Conversion

Energy conversion is the process by which energy changes from one form to another. In this problem, mechanical work is converted into thermal energy through the action of friction. This principle is governed by the conservation of energy, affirming that energy is neither created nor destroyed, only transformed between different forms.

Transcript

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