A student strikes a block at the bottom of a ramp giving it an initial speed v0 up the ramp as shown at right. there is a friction between the ramp and the block

When we move the block on the ramp, the friction force is the force which opposes its motion.

Explanation:

When we apply force in the forward direction, the block moves horizontally on the floor or ramp. The force which oppose the motion of the block is known as force of friction. When the block is at rest, static friction act upon it which prevent the block from movement but when the block start motion, this static friction replace by the kinetic friction which opposes the moving body and reduce the speed.

b. as prices rise, quantity demanded goes down.

like many students at university, you may be unhappy about the results you attain in exams. you may feel that even with all you are doing there must be something more -- or different-- you could be doing to get better grades. we have all at some time or other heard of that student who only studies a couple of hours for final exams and scores a's every time. we stand in awe of those who seem to breeze through without undue effort and seem to need very little in the way of studying to nail an exam. the reasons for success, in what i think are the vast majority of cases, are less esoteric than many students think: successful students consistently apply a series of productive strategies with view to attaining clearly identified learning and grade goals throughout the academic term.