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(a) What is the magnitude of F when the crate is in this final position? 1 N (b)

ID: 1673161 • Letter: #

Question

(a) What is the magnitude of Fwhen the crate is in this final position?
1 N

(b) During the crate's displacement, what is the total work done onit?
2 J

(c) During the crate's displacement, what is the work done by theweight of the crate?
3 kJ

(d) During the crate's displacement, what is the work done by thepull on the crate from the rope?
4 J

(e) Knowing that the crate is motionless before and after itsdisplacement, use the answers to (b), (c), and (d) to find the workyour force F does on the crate.
5 kJ

(f) Why is the work of your force not equal to the product of thehorizontal displacement and the answer to (a)?
6

Explanation / Answer

   From the figure the angle is           =Sin-1( 4.0m / 12.m)             = 19.5o        The tension in the ropeis           T = 240kg (9.8) /Cos19.5o              = 2495N The force F = (2495N )Sin19.5                    = 832.85 N b) there is no change in kinetic energy the total workdone is zero. c) The work done by the gravitational force is           Wg = - m g L [ 1 - Cos19.5]                  =(240) (9.8) [ 1 - cos19.5]               = - 1618.88J d)here the angle is 90         W = 0   e) The work done by the force is       W = -  Wg = 1618.8J From the figure the angle is           =Sin-1( 4.0m / 12.m)             = 19.5o        The tension in the ropeis           T = 240kg (9.8) /Cos19.5o              = 2495N The force F = (2495N )Sin19.5                    = 832.85 N b) there is no change in kinetic energy the total workdone is zero. c) The work done by the gravitational force is           Wg = - m g L [ 1 - Cos19.5]                  =(240) (9.8) [ 1 - cos19.5]               = - 1618.88J d)here the angle is 90         W = 0   e) The work done by the force is       W = -  Wg = 1618.8J e) The work done by the force is       W = -  Wg = 1618.8J