When walking barefoot, Kevin can walk across the grass easily, but when he crosses the paved street, the street is hot and burns his feet. At the beach he walks quickly across the hot sand to the cool water. Why do some substances feel hot to his feet and others do not? Radiation is heat transfer through waves. Specific heat is the amount of energy required to raise the temperature of a substance 1 degree C.

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?