Distinguishing between Speed and Velocity A 100-meter sprint is a race using only the straight side of
a racetrack. A 400-meter sprint is a race that makes one
complete lap around a racetrack. Why are velocity and
speed the same for a 100-m sprint but not a 400-m sprint?

there are two significant figures.

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.