- 59

- 0

**1. The problem statement, all variables and given/known data**

A 4.8 g marble is fired vertically upward using a spring gun. The spring must be compressed 8.0 cm if the marble is to just reach a target 27 m above the marble's position on the compressed spring.

(a) What is the change in the gravitational potential energy of the marble-Earth system during the 27 m ascent?

(a) ? J

(b) What is the change in the elastic potential energy of the spring during its launch of the marble?

(b) ? J

(c) What is the spring constant of the spring?

(c) ? N/m

**2. The attempt at a solution**

(a)

27 - .080 = 26.92

(26.92)(9.8)(.0048) = (1/2)(.0048)v^2

v = 22.97 <<<< Isn't this the answer? But it's wrong.

(b)

(1/2)(the answer to c: ?)(.080)^2

(c)

(1/2)(.0048)(the answer to a: 22.97?)^2 + (.0048)(9.8)(.080) = (1/2)(k)(.080)^2

k = ?