4. An "extreme" pogo stick utilizes a spring whose uncompressed length is 46 cm and whose force constant is 1.4 x 104 N/m. A 60-kg person is jumping on the pogo stick,
compressing the spring to a length of only 5.0 cm at the bottom of their jump. Which is the upward acceleration of the person at the moment the spring reaches its greatest
compression at the bottom of their jump?
6 m 2

a = 85.9 m / s²

Explanation:

For this exercise we can use Newton's second law in the most compressed part

             F - W = m a

force is the spring elastic force

             F = - k Δx

          k Δx - m g = m a

          a = k/m  Δx - g

         Δx = x₀ -

         ΔX = 46 - 5 = 41cm (1m / 100cm) = 0.41  m

let's calculate

          a = 1.4 10⁴/60 0.41 - 9.8

          a = 85.9 m / s²

their crystal patterns have been disrupted by stress