Define force and speed​

Force = The external energy that changes or tends to change the state of any body or object is called force.

Speed = The rate of distance is called speed.

Force is a push or pull which changes or tend to change the position of a body.

The rate of change its position with time or magnitude is called speed.

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

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.