- #1

Sciencelover91

- 11

- 1

## Homework Statement

Imagine you were to connect your spring from this experiment to a 1.0 kg lab cart. You pull the car back and stretch the spring 30 cm, then release the car from rest, assuming there is no friction.

A) find the acceleration at the instant when the cart is first released.

B) When the spring's stretch has decreased to 20 cm (thus the cart has moved forward 10 cm), calculate the cart's acceleration at this instant.

## Homework Equations

I have this equation that I solved for from my lab data: Force of spring = (spring constant 7.5N/M) x (the stretch of the spring s). ----> Fos (force on string) = 7.5 N/m (s)

F=ma

## The Attempt at a Solution

a) I know I am given the mass of the cart, initial velocity (0m/s) and the stretch of the string so I tried using f=ma and used Fos = ma.

7.5N/m (.2 m) = (1.0kg) X a

a = 2.25 m/s^2

However I think it's supposed to take into consideration that the initial velocity is zero so I don't know how to apply this without the final velocity.

B) I did force on spring = ma so 7.5(.2m) = 1.0kg x a and got 1.5 m/s^2, I want to know if I did this correctly and if I was supposed to use the fact that it moved 10cm forward.