Which statement describes how the weathering shown in this picture occurred? Water from a waterfall beats the rocks at its base, breaking them apart.

Tree roots climb into cracks in rocks causing pressure that splits the rocks as the roots grow.

Wind carries grains of sand and dirt that hit the surface of a rock.

Water that has seeped into a rock expands as it freezes, pushing out every tiny crevice it has dripped into.

Snow on Mountain Rocks

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.