Pre-PhysicsLab

Pre Lab 5 Read Lab 5

1) A spring is hanging from a post with total length 𝐿0 as shown. When a mass 𝑚1 is added to the spring the spring stretches to a new length 𝐿1. 1a) How would you calculate the force and the stretch of this spring in terms of 𝐿0, 𝐿1, 𝑔, and 𝑚1?

1b) How would your answer for the stretch change if 𝐿2 and 𝐿3 were measured from the floor (instead of the top of the spring) as shown?

2) The force and the stretch of a spring has been measured for six different masses while they are at rest hanging from the spring shown above. Plot the data below and using a scatter plot with a linear trendline through your points to find the best fit value for the spring constant 𝑘 of the spring assuming the force obeys the formula 𝐹 = 𝑘(𝑠𝑡𝑟𝑒𝑡𝑐ℎ) + 𝑓0.

stretch (m) Force (N)

.05 2

.093 3

.142 4

.187 5

.25 6

3) You measure the position, velocity and acceleration of the mass pictured above while it

is bouncing up and down. Write down a formula that relates the acceleration of the mass to the stretch of the spring. If you create a plot of ‘a’ vs ‘stretch’, what does the slope represent? What does the y intercept represent?

𝐿0 𝐿1

𝐿2 𝐿3