Question Follow-Up

Q1 – Newton

• Pedro tosses a 0.1 kg boomerang straight up in the air with a velocity of 10 m/s. What is the potential energy of the boomerang when it reaches its maximum height? (Assume no energy losses during flight)

Question Summary

• “This question is asking me to figure out the potential energy of a thrown object when it gets to its highest point.”

What I Know

• Kinetic Energy + Potential Energy = Total Energy

• Total Energy remains constant in this system• When the ball is at its peak, it will have no

Kinetic Energy because it will not be moving.• KE = ½*mass*velocity^2• PE = mass*g*height• Mass = 0.1kg, Velocity = 10m/s

What I Need to Know

Starting Kinetic Energy– KE = 1/2*m*v^2– KE = ½(0.1kg)(10m/s)^2– KE = ½*0.1 kg*100 m2/s2– KE = 5 kg*m2/s2 = 5 Joules

Solution

• If no energy is lost, the maximum kinetic will be when the ball has the greatest speed.

• The maximum potential energy will be when the ball has the greatest height.

• The max PE will be equal to the starting KE.• The PE at the object’s highest point will be 5

Joules.

Follow-Up Question

• How high will the ball travel?• At what height will Kinetic and Potential

Energy be equal?• If the boomerang doubled in weight, how

would that affect its height if Pedro throws with the same initial Kinetic Energy?

Q2: Sad• A 79-year-old man is brought to the ED by his

family. He is essentially mute, has had frequent crying episodes and has complained of a decrease in energy that has lasted about 3 weeks. He has lost 15lb in 3 weeks, and told his family that “it would be better if I were not around any more”. He exhibits psychomotor slowing and when asked if suicidal, he nodded yes. When asked “are you hearing voices”, he nods “yes”. What is the most likely diagnosis?

Question Summary

• “A man comes into the office with multiple complaints that suggest major depression. Does he meet criteria for MDD or for another disorder?”

What I Know – Pertinent Positives/Negatives

• Mutism• Decreased energy• Significant weight loss• Guilt• Psychomotor slowing• Suicidal thoughts• Hallucinations

What I Need to Know

• Criteria for Major Depressive Disorder– Symptoms for 2 weeks?– Do symptoms affect functioning?– At least 5 SIG-E-CAPS symptoms?

• Other conditions to Rule Out– History of mania Think bipolar disorder– Substance abuse think substance-abuse mood d/o– Hallucinations before depression think schizoaffective

Solution

• 5 symptoms – 1.)weight loss, 2.)loss of energy, 3.)depressed mood, 4.) suicidal thoughts, 5.) psychomotor retardation, 6.)feelings of guilt

• What’s up with the hallucinations?• Can we rule out other diagnoses?

Follow-Up Questions

• Likely diagnosis if 2 months ago he bought a Ferrari on a credit card, hired prostitutes on a nightly basis, and built a 10 foot Ferris wheel for hamsters in his back yard?

• Likely diagnosis if he was a 20 year old who showed up with these symptoms along with a 6 month history of increasing isolation, paranoia, and had apparently been talking to imaginary friends.

Follow-Up Questions

• Treatment options• Mechanism of action of common

pharmaceutical therapies• Likely prognosis/natural history of disease• Comorbid conditions