a student is walking home from school. after 5 minutes it starts to rain lightly, so the student walks a little faster. after another 2 minutes it starts to rain hard, and the student runs the rest of the way home. the total time the student takes to get home in 10 minutes. which gragh below best represents the students motion during the trip home.

A

Explanation:

complete question with the graphs are attached to this answer.

Let us consider the question closely. When the student was walking home, his/her speed was uniform. However, after 5 minutes, the student increased his/her pace due to the light rain. This is seen as a slight increase in speed after 5 minutes on the graph A. two minutes after (at the 7th minute) the rain comes hard and the student had to increase his/her speed by a much higher magnitude by running and maintaining this uniform speed all the way untill the end of the journey at the 10th minute.

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.