Hw 8 force 2
here is a linearly variable force problem.
question 1
a land-sled is 100 kg in mass. it rides on a flat ground whose coefficients of friction are 0.70 for
kinetic and 0.80 for static. the land-sled is propelled by an engine that pushes the sled with on
to 2000 n linearly over a total time of 20 seconds in the horizontal direction. here is a plot of the
engine's force on the sled. ignore the fact that the sled gets lighter as fuel is consumed.
engine
asled
2000n
20 s
20 s
.
a. taking friction into account, what does the acceleration function of the sled look like? sketch it
with labels and units on the graph given above?
b. write down the acceleration function as a function of time along with the domain in which this
function is valid. attach to any constant its unit as well.
c. what are the equations of motion for this situation?
d. if the sled starts at rest, what is the velocity of the sled at 20 seconds?
e. what is the displacement of the sled over this 20 seconds?
here is a spring force problem

What is the final velocity of the initial velocity of 25 and -50?

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0

Which statement describes the formation of our sun? a disk formed of long trails of stars coiled into a spiral. it formed an elliptical flattened disk. heat and gases contracted within a nebula. gravity pushed stars away from a center core.