A spring is mounted at an angle of theta = 39degrees on a frictionless incline as illustrated in the figure below. The spring is compressed to 15 cm where it is allowed to propel a mass of 4.9 kg up the incline.(adsbygoogle = window.adsbygoogle || []).push({});

(a) If the spring constant is 580 N/m, how fast is the mass moving when leaves the spring?

m/s

[5 points] 5 attempt(s) made (maximum allowed for credit = 5)

[after that, multiply credit by 0.5 up to 10 attempts]

1.864 NO

(b) To what maximum distance from the starting point will the mass rise up the incline?

m

2. Relevant equations

i have no clue what is correct because i have tried so many different ones

3. The attempt at a solutionbut for some reason this is not the correct answer

Step One

=======

Find the Force created by the spring

F = kx

k = 580 N/m

x = 15cm = 15*[1 m/100 cm] = 0.15 m

F = 580*0.15 = 87 N

Step Two

=======

Find the force created (in opposition) by the mass trying to slide down the incline.

The formula for the force trying to go down the incline is F = mg*sin(A)

A = 39o

m = 4.9 kg

g = 9.81 m/s^2

F-incline = 4.9*9.81 * sin(28)

F-incline = 30.25 N

Step Three

========

Find the net upward force created by the spring.

F-net = F-spring - F-incline

F-net = 87 - 30.25= 56.75

Step Four

=======

Find the acceleration.

F = m*a

56.75 = 4.9*a

11.58 m/s^2 = a

Step Four

=======

Find the final velocity of the mass as it departs from the spring.

vi = 0

a = 11.58

d = 0.15 m

vf = ??

vf^2 = vi^2 + 2*a*d

vf^2 = 0 + 2*11.58*0.15

vf^2 = 3.47

vf = 1.86 m/s

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Mass-spring system on an incline

**Physics Forums | Science Articles, Homework Help, Discussion**