- #1
cristina
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A 3kg object moving along the x-axis has a velocity of 2.40m/s as it passes through the origin. It is acted on by a single force Fx that varies with x as shown...
a) find the work done by the force from x=0 to x = 2m
b) what is the kinetic energy of the object at x=2m?
c) what is the speed of the object at x=2m?
d) find the work done on the object from x=0 to x=4
e) what is the speed of the object at x =4m
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a) I know since the force is variable the work is equal to the area under the curve Fx-versus-x. I don't know which value of F should I put in the Work integral equation S fx dx.
b) k = 1/2mv^2 =1/2(3kg)v^2
the force on the curve at x=2 is F = 1.9N can I put it the Newton second law equation Ftotal = ma, 1.9N = 3kg x a ,
a = 1.9N/3kg = 0.63 m/s^2 and then since I got the acceleration I pluge it in v^2 = v + 2(a)(dleta x) = (2.40m/s)+2(0.63)(2m-0m)= 4.92
so v = 2.22m/s ?
d) before x=4m actually at x = 3m the curve go under the x-axis
I will integrate the part from x=0 to x=3 and then subtract from it the integration from x=3 to x = 4. but again I don't know what force should I use in the work integration fromula.
I thank you in advance of your help.
a) find the work done by the force from x=0 to x = 2m
b) what is the kinetic energy of the object at x=2m?
c) what is the speed of the object at x=2m?
d) find the work done on the object from x=0 to x=4
e) what is the speed of the object at x =4m
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a) I know since the force is variable the work is equal to the area under the curve Fx-versus-x. I don't know which value of F should I put in the Work integral equation S fx dx.
b) k = 1/2mv^2 =1/2(3kg)v^2
the force on the curve at x=2 is F = 1.9N can I put it the Newton second law equation Ftotal = ma, 1.9N = 3kg x a ,
a = 1.9N/3kg = 0.63 m/s^2 and then since I got the acceleration I pluge it in v^2 = v + 2(a)(dleta x) = (2.40m/s)+2(0.63)(2m-0m)= 4.92
so v = 2.22m/s ?
d) before x=4m actually at x = 3m the curve go under the x-axis
I will integrate the part from x=0 to x=3 and then subtract from it the integration from x=3 to x = 4. but again I don't know what force should I use in the work integration fromula.
I thank you in advance of your help.