Question

一个力F作用在质量为1kg的质点上,使之沿X轴运动.

Answer 1

1.

运动方程两边对时间求导

v = 3 - 8t + 3t²(SI)

v(0) = 3 m/s,v(4) = 19 m/s,

I = Δ(mv) = mΔv = 16 N·s.

2.

W = ΔEk = Δ(mv^2/2) = mΔ(v²)/2 = 176J.

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