- #1
SChiO
- 11
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Homework Statement
A block slides from rest down a frictionless ramp which is 4 m long and has a 30 degree angle with respect to the ground. After reaching the bottom of the ramp it slides on a frictionless surface and compresses a spring a distance of 12cm (.12m) before coming to rest momentarily.
a) What is the speed of the block before striking the spring?
b) What is the spring constant?
The Attempt at a Solution
I wanted to see if I was on the right track...my logic is to use conservation of energy. Setting my initial condition as the block sliding down the ramp and my final condition when it comes to rest after compressing the spring...So the sum of my initial energy would by equal to the kinetic energy and the sum of my final energy is equal to the potential energy --> 1/2mv2 = mgh
Solving for v you get v = √(2gh)...I was thinking the "h" is the height of the ramp which can be found using the angle...I got 2m for that. So using 9.8 m/s2 for g and plugging the rest into my equation I got a velocity of 6.2 m/s
To find the spring constant I figured you could use F = -kx and solve for F. With a free body diagram the only force acting on the block is gravity but without a mass, I don't know how to find the quantity of that force...
Please help with part b! And does the work for part a seem correct?? Really appreciate it, I have my final tomorrow and want to be sure I can do these problems correctly!