If the block was moving west and the spring was pushing the block east to stop it, would the equation then be F(x) = kx or it would it still F(x) = -kx since the spring is slowing the block down? Because wouldn't it still be considered negative work?
Does it make sense that I am leaving the spring constant negative and subtracting the work done by friction? I was thinking that should be the case since its vector is going the same direction as the spring is pushing or am I wrong about this? I saw a similar problem online and the spring...
Equation 1: T = Ma1
Equation 2: mg - 2T = ma2
Equation 3: a1 = 2a2
Since a1 = 2a for equation one I get T = 2Ma1
mg - 4Ma1 = ma1
mg = 4Ma1 + ma1
mg = 4a1(M+m)
a1= mg / 4M+m
Not sure if this is correct. Can someone please help to make sure I'm doing this right?
Thanx
W_net = Integral from 0 to 0.70 meters [ - F_spring - F_friction ]
= 1/2 * (-k) * x^2 - mu * mg * normal force * x
= 1/2 * (-325N/m) * (.70)^2 - 0.250 * 6kg * 9.81m/s^2 * 0.70 - 0
= - 89.93 Joules
Is this correct and am I setting this whole thing up correctly? The negative signs have me...