In a controlled scientific experiment,
OA.
all variables are kept constant.
OB. no variables are kept constant.
Oc. one or more variables are kept constant.
OD. only one variable can be kept constant.

answer seismograph;

the correct answer would be b) volume versus temperature, because they are also directly proportional.

gasoline is a mixture. it contains several different kinds of compounds that can be present in a variety of ratios.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.