# Spring constant, pendulums and and angular momentum all rolled into one

• heatherjones.
In summary, a block on a slope with a spring compressing it is released and travels up the slope towards an inverted pendulum. The angle of the slope and the angle between the pendulum and the vertical axis are both 20 degrees, and the angle between the slope and the pendulum is 90 degrees. There is no friction and the rod of the pendulum is mass-less. The spring is originally compressed by 4.5cm and the block travels a distance of 45cm. The pendulum's rod is 17cm in length, the mass of the block is 0.45kg, and the mass of the bob at the end of the pendulum is 0.38kg. Both masses stick together
heatherjones.
there is a block on a slope (that is compressing a spring) and it is released and fired up the slope towards an inverted pendulum (that's leaning on the end of the slope) with just enough speed that the combination reaches (Theta)=0 degrees with no speed.

Find the Spring constant

the angle of the slope is 20 Degrees, the angle between the leaning pendulum and the vertical axis is also 20 degrees. the angle between the slope and the pendulum should be 90 degrees

there is no friction,
the rod of the pendulum is mass-less
the distance the spring is originally compressed is (delta)x=4.5cm
the block travels a distance of L=45cm
the rod of the pendulum is R=17cm in length
mass of the block is m2=.45 kg
mass of the bob at the end of pendulum is m1=.38kg

both the masses stick together

there was no more information given, and this was a spur of the moment question the teacher created in class.

i drew a picture too if that could help, http://imageshack.us/photo/my-images/42/physixprblem.png/

we didn't get to finish it in class and no one could figure out how to solve it yet.can anyone manage to figure out how it works? i showed my professor my work and still i don't understand where i went wrongi know energy of angular momentum is conserved and the collision does not conserve energy... but when i looked back over my notes i still don't even know where to begin again on this problem.

i think it involves the following formulas at the very least, but i never got any further! i know it requires more than this...

Kinetic(rotational)=(1/2)(Inertia)(omega)
Potential(bob)=mgh
L(angular momentum)=Inertia*(Omega)

Last edited:
I would post this in the Homework forums to ensure you get the best help possible, as per PF rules!

## 1. What is the spring constant?

The spring constant, also known as the force constant, is a measure of how stiff a spring is. It is represented by the letter k and is calculated by dividing the force applied to the spring by the amount of displacement it causes.

## 2. How does the spring constant affect a pendulum?

The spring constant affects a pendulum by determining the frequency of its oscillations. A higher spring constant will result in a faster oscillation frequency, while a lower spring constant will result in a slower frequency.

## 3. What is the relationship between spring constant and angular momentum?

The spring constant and angular momentum are not directly related. However, the spring constant can affect the angular momentum of a pendulum by influencing its oscillation frequency, which in turn affects the speed and direction of the pendulum's rotation.

## 4. How does the length of a pendulum affect its spring constant?

The length of a pendulum does not affect its spring constant. The spring constant is determined by the properties of the spring itself, such as its material and shape, and is not affected by external factors like the length of the pendulum.

## 5. Can the spring constant be changed?

Yes, the spring constant can be changed by altering the properties of the spring, such as its material, length, or thickness. The force applied to the spring can also affect its spring constant, as well as the temperature and other environmental factors.

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