# Homework Help: What is the force of the spring constant?

1. Jun 17, 2012

### tgould43

If a spring is originally compressed by 6cm, what is the force of the spring constant?
A block of inertia m=0.2kg is launched from a spring onto frictionless surface. The velocity is 2.5m/s upon leaving the spring.
I used Hooke's law and got
k=mg/x
0.2kg x 9.8m/s / 0.06m = 32.7 N/m
The next question is if this spring was used to suspend a 3kg block from ceiling what would the displacement of the spring be?
I need some help with the ratio of what is needed to solve this problem

2. Jun 17, 2012

### tgould43

would the equation change by the new equation of
3.0kg x 9.8 ms / .06 = 490 N/m

3. Jun 17, 2012

### tgould43

My mind keeps thinking that there is some relationship between the displacement of the 2.5 m/s velocity of the first block after it left the spring. Is this something that is valid?

4. Jun 17, 2012

### Staff: Mentor

You'll need to describe the problem more carefully. Is the mass launched horizontally?
That would be true if the mass were placed on a vertical spring and allowed to come to equilibrium. Is that what's going on here?