CH07.Problems

JH.131

• Position velocity acceleration force• 2 times & position displacement• Force & displacement work

• V= -10 t, a= -10, F= -10*5=-50 N;• Xi= 10, Xf= 10-5*16, d = -80 m• W = F . D = 4 000 J

K =1/2 m V^2, doubling V makes V^2 4 times higher, Vi Vf=2 ViThus Ki Kf= 4 Ki

Ws = ½ k (Xi^2 - Xf^2)

Or

Fs = -k X and Ws = - Fs * x Negative of the integral

Take two triangles: ½ 8 * (-80) + ½ (-4) * 40 = -240 N cm = - 2.4 JThen W = - integral =+2.4J