Elastic energy, spring equation. Help?

AI Thread Summary
The discussion centers on calculating the height a block reaches after being launched from a compressed spring. The user initially applies the equations incorrectly, mixing up the energy stored in the spring and the gravitational potential energy. The correct approach involves using the spring's potential energy formula, Eel = 1/2 * k * x^2, to find the energy converted into gravitational potential energy, Eg = mgh. The user realizes the mistake and acknowledges the correct method for solving the problem. Understanding the transformation of energy is crucial for accurate calculations in such physics problems.
mrphobio
Messages
27
Reaction score
0

Homework Statement


A 293g block is placed on a spring with a spring constant of 161N/m, compressing it 42cm. What height does the block reach when it is launched?

Homework Equations


Eel=1/2*k*x2
Eg=mgh

The Attempt at a Solution


Eg=.293*10*.42=1.2306

1.2306=1/2*161*x2
1.2306=80.5x2
.0153=x2
.1236=x

Did I make any mistakes? Because I can't get it right.

------------------------------------------------------------------------
nevermind i got it..
 
Last edited:
Physics news on Phys.org
Hi mrphobio,
You're using the equations the wrong way round.
The energy stored in the spring (0.5kx2) with spring constant k and compression of the spring x.

Since energy can't be destroyed, it is transformed into kinetic energy, and finally into potential energy (mgh) with mass m and height of the object h.

Hope this helps.
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Find elastic energy in the compressed spring.
Replies
12
Views
3K
Distribution of Energy when work is done on a system of 2 masses connected by a spring
Replies
17
Views
2K
Building a Marble Catapult
Replies
3
Views
898
Question about springs and rotational/translational energy
Replies
4
Views
1K
Problem with when to use Force and Energy. What compresses spring/
Replies
3
Views
1K
Spring Problem Involving Variables and Constants Only
Replies
3
Views
1K
Calculating the spring force constant K
Replies
14
Views
2K
GRADE 12: Energy, Springs and maybe momentum/collisions?
Replies
5
Views
2K
A rocket on a spring, related to potential/kinetic energy
Replies
3
Views
2K
A block of mass m is dropped onto the top of a vertical spring....
Replies
8
Views
5K

Hot Threads

Recent Insights

Back
Top