The force applied against an object moving horizontally on a linear path is described by #F(x)= x+3 N #. By how much does the object's kinetic energy change as the object moves from # x in [ 1 , 2 ]#?

1 Answer
Dec 29, 2015

Answer:

It increases by #4"J"#

Explanation:

Work done = force x distance moved in direction of force.

Because force varies with displacement we can say:

#W=int_1^2F.dx#

#:.W=int_1^2(x+3).dx#

#W=[x^2/2+3x]_1^2#

#W=[4/2+6]-[1+3]#

#W=8-4=4"J"#

This work will appear as kinetic energy.