When an 86.5-g piece of toast is inserted into a toaster, the toaster's ejection spring is compressed 7.85 cm. When the toaster ejects the toasted slice, the slice reaches a height of 3.9 cm above it's starting position. What is the average force that the ejection spring exerts on the toast? What is the time over which the ejection spring pushes on the toast. Assume that throughout the ejection process the toast experiences a constant acceleration.
Not sure. I'm confused about 'assumptions' with the question. Seems broken to me. I approached it using different ways; 1. finding the spring constant of the spring, plugging that into the force formula [f=kx] OR ignoring the fact that the spring is a spring, then comparing forces [setting them equal to each other] and solving for some variable. The first method seems to work, but has given twice the correct answer. I'm not looking for the answer, I'm looking for the methodology.
The Attempt at a Solution
k= (2mg(3.9cm+7.85cm) / (7.85cm^2)) = 32.36
f= k x
f= (32.36) (.039 - .0785) = 1.27822 N
correct answer is: 1.27 N