Nanabit
Oct7-03, 01:04 PM
A block of mass 12.0 kg slides from rest down a frictionless 37.0 degree incline and is stopped by a strong spring with k=3.50e4 N/m. The block slides 3.00 m from the point of release to the point where is comes to a rest against the spring. When the block comes to rest, how far has the spring been compressed?
I really wanted to use 1/2kx^2 = W to get this, but I know I didn't have all of the values. I thought of using KE = 1/2 mv^2, but I don't know how to get velocity without a time value. So I ended up using an equation for the incline, g sin theta = acceleration, got 5.90 m/s^2 for that, plugged mass and acceleration into f=ma to get a force of 70.8 N, plugged values into W=F S Cos theta to get work as 170 J, and finally plugged values into 1/2kx^2 = W to get x as .0984, but this is wrong. For every other equation I try to use, I'm missing 2 values and don't know how to get either of them. Where did I go wrong?
I really wanted to use 1/2kx^2 = W to get this, but I know I didn't have all of the values. I thought of using KE = 1/2 mv^2, but I don't know how to get velocity without a time value. So I ended up using an equation for the incline, g sin theta = acceleration, got 5.90 m/s^2 for that, plugged mass and acceleration into f=ma to get a force of 70.8 N, plugged values into W=F S Cos theta to get work as 170 J, and finally plugged values into 1/2kx^2 = W to get x as .0984, but this is wrong. For every other equation I try to use, I'm missing 2 values and don't know how to get either of them. Where did I go wrong?