Atennis ball traveling horizontally at a speed of 40 m/s hits a wall and rebounds in the opposite direction. the time interval for the collision is about 0.013 s, and the mass of the ball is 0.059 kg. assume that the ball rebounds at the same speed.

(a) determine the initial and final momenta of the ball. assume the initial velocity direction is positive.

(b) determine the change in momentum of the ball.

(c) determine the average force exerted by the wall on the ball.

Answer

given,

initial velocity of the ball, u = 40 m/s

final velocity of the ball, v= -40 m/s

time of contact = 0.013 s

mass of the ball = 0.059 Kg

a) initial momentum

   P₁ = m u = 0.059 x 40 = 2.36 kg.m/s

  final momentum  

   P₂ = m v = 0.059 x (-40) = -2.36 kg.m/s

b) change in momentum

      Δ P = P₂- P₁

      Δ P = -2.36 - 2.36

     Δ P = -4.72 kg.m/s

c) Average force

 average force exerted by the ball is equal to change in momentum per unit time.

            F = -363 N

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.

terd muffin is the correct answer