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lemonpie
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Homework Statement
A 3.0 kg body is at rest on a frictionless horizontal air track when a constant horizontal force acting in the positive direction of an x-axis along the track is applied to the body. A stroboscopic graph of the position of the body as it slides to the right is shown in Figure 7-26. The force is applied to the body at t = 0, and the graph records the position of the body at 0.50 s intervals. How much work is done on the body by the applied force between t = 0 and t = 2.0 s?
http://www.lowellphysics.org/beta/Textbook%20Resources/Chapter%207.%20Kinetic%20Energy%20and%20Work/Problems/c07x7_11.xform_files/nw0308-n.gif
Homework Equations
um... v = x/t, a = v/t, F = ma, W = Fd?
The Attempt at a Solution
delta v = x/t = 0.8/2 = 0.4 m/s
delta a = v/t = 0.4/2 = 0.2 m/s^2
F = ma = 3*0.2 = 0.6 N
W = Fd = 0.6*0.8 = 0.48 J
This is not the correct answer. The correct answer is 0.96 J, twice my answer. What am I doing wrong? Please help me. This is not an assigned problem for points; it's just to help me understand.