Find a formula for the change in surface area of a uniform solid sphere of radius r if its coefficient of linear expansion is α (assumed constant) and its temperature is changed by δt.

i know the answer isδa = 8π r^2αδt [1+(1/2)αδt]

and that the problem involves linear expansion, but im not sure how to arrive at this equation. explain and show steps.

Scout feels ill one day before school. her mother puts a thermometer in her mouth and the temperature begins to climb to 100°f. what is happening between the cooler thermometer and scout's body? a) scout's body is applying a force to the particles in the thermometer. b) kinetic energy is being transferred from her mouth to the thermometer. c) potential energy is being lost by the thermometer and gained by scout's body. d) the potential energy stored in foods is converted to mechanical energy to raise the mercury in the thermometer.

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

Which of the following is not a means to accelerating? question 4 options: a)increase speed b)remain still c)decrease speed d)change direction