Ablock of mass m slides along a horizontal surface lubricated with a thick oil which provides a drag force proportional to the square root of velocity: fd=−bv^1/2.
if v=v0 at t=0, determine v as function of time.
determine x as function of time. assume that x=0 at t=0.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.

Why does lightning travel from clouds to the ground?