Workers use a force of 2125 N to push a piano weighing 8800 N up a 20.0 m long ramp. a.) How
much work is done on the piano by the workers in pushing it up the ramp?

b.) The piano is being
moved from street level to the second floor of a building. The second floor is 4.0 m above street level.
If the workers decide to lift the piano straight up by using ropes, how much work would they do?

c.) What is the efficiency of the ramp?

4. who was the first one to measure the speed of light and conclude that it is finite? 5. who was the first philosopher who thought the speed of light is finite? 13. what is the speed of light numerically? 14. give an example of something moving faster than light 15. give an example for some particles or waves that

For this car, predict the shape of a graph that shows distance (x) versus time (t). note that time is the independent variable and will be on the bottom axis. need asap

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".