A12.0-g bullet is fired horizontally into a 104-g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 154 n/m. the bullet becomes embedded in the block. if the bullet-block system compresses the spring by a maximum of 83.0 cm, what was the speed of the bullet at impact with the block?

 v₀ = 292.3 m / s

Explanation:

Let's analyze the situation, on the one hand we have the shock between the bullet and the block that we can work with at the moment and another part where the assembly (bullet + block) compresses a spring, which we can work with mechanical energy, as the data they give us are Let's start with this second part.

We write the mechanical energy when the shock has passed the bodies

    Em₀ = K = ½ (m + M) v²

We write the mechanical energy when the spring is in maximum compression

    = = ½ k x²

    Em₀ =

    ½ (m + M) v² = ½ k x²

Let's calculate the system speed

    v = √ [k x² / (m + M)]

    v = √[154 0.83² / (0.012 +0.104) ]

    v = 30.24 m / s

This is the speed of the bullet + Block system

Now let's use the moment to solve the shock

Before the crash

    p₀ = m v₀

After the crash

    = (m + M) v

The system is formed by the bullet and block assembly, so the forces during the crash are internal and the moment is preserved

   p₀ =  

   m v₀ = (m + M) v

   v₀ = v (m + M) / m

let's calculate

   v₀ = 30.24 (0.012 +0.104) /0.012

   v₀ = 292.3 m / s

sleep paralysis is a parasomnia, events associated with sleep.

sleep paralysis happens when you are in the middle of waking up or falling asleep. it is the feeling of being conscious but unable to move. it definitely involves hallucinations.

i had a friend that had sleep paralysis and he told me a story one time where he was laying in bed and he couldn't move his body no matter how hard he tried and there was someone standing in the corner of his room coming towards him. he couldn't move and you can't "wake up" because you are already conscious. sometimes sleep paralysis can be triggered by frequent waking up during the night based off of multiple trips to the bathroom, or if you had ever been abused, sleep paralysis can start happening from things like that.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba