korosh23
  • korosh23
Bob throws a 0.50 kg baseball straight up. At a height of 30.0 m it is moving at 12m/s a) what is the ball's kinetic energy? b) What is the gravitational potential energy of the ball? c) How much work was done by Bob to get the ball up into the air?
Physics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
m=0.50 kg h=30 m v=12m/s a. apply the kinetic energy formula \(\sf KE= \frac{1}{2}mv^2\) b. apply the potential energy formula \(\sf PE= mgh \), where g is the acceleration due to gravity. c. apply work energy theorem: \(\sf W=\Delta E\)
korosh23
  • korosh23
Thank you for mentioning the formulas. I already know how to use them, I did part a and b, but not c. Could you please explain me how to do it?
korosh23
  • korosh23
@Michele_Laino

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

korosh23
  • korosh23
I do not know how to do C.
Michele_Laino
  • Michele_Laino
I'm pondering...
korosh23
  • korosh23
Ok. My teacher gave me the answer. He did not show the work. Do you want the answer? Maybe it can help you to find how?
Michele_Laino
  • Michele_Laino
ok!
korosh23
  • korosh23
46) a) 36J b) 150J c) 180J
Michele_Laino
  • Michele_Laino
part a) \[KE = \frac{1}{2}m{v^2} = \frac{1}{2} \times \frac{1}{2} \times 144 = 36Joules\]
korosh23
  • korosh23
Yes
Michele_Laino
  • Michele_Laino
part b) \[PE = mgh = \frac{1}{2} \times 10 \times 30 = 150Joules\] here g=10 m/sec^2
korosh23
  • korosh23
Yes
korosh23
  • korosh23
It is challengic! :D
Michele_Laino
  • Michele_Laino
yes! Lol! for part c) we can write this equation: \[\Large \frac{1}{2}mv_{INITIAL}^2 - \frac{1}{2}mv_{FINAL}^2 = mgh\]
korosh23
  • korosh23
No,
Michele_Laino
  • Michele_Laino
where v_FINAL= 12 m/sec
korosh23
  • korosh23
ok go on
Michele_Laino
  • Michele_Laino
and v_INITIAL is the starting speed of your ball
korosh23
  • korosh23
Starting speed is o m/s
korosh23
  • korosh23
I think
Michele_Laino
  • Michele_Laino
it is impossible, since v_INITIAL =0 then the ball can not go away
korosh23
  • korosh23
Then how the answer is 180J? You are tight it is impossible.
korosh23
  • korosh23
One more question? it is important for me to know.
korosh23
  • korosh23
easy for you
Michele_Laino
  • Michele_Laino
I think that it is an approximated value, since the work done by Bob has to be equal to the initial kinetic energy
Michele_Laino
  • Michele_Laino
namely: \[W = \frac{1}{2}mv_{FINAL}^2 + mgh = 36 + 150\]
korosh23
  • korosh23
W is change in kinetic energy, but not mechanical energy. It is fine, we can move to another question.
korosh23
  • korosh23
May I ask you my another question?
Michele_Laino
  • Michele_Laino
W is the work done by Bob. more explanation: if the ball is thrown by a compressed spring, then we can say that the potential energy of the spring is equal to the kinetic energy of the ball, so the work done by the spring on the ball is equal to the initial kinetic energy of our ball
Michele_Laino
  • Michele_Laino
the same reasoning goes if we replace the spring with Bob
korosh23
  • korosh23
Ok. Makes sense.
korosh23
  • korosh23
Can I ask you one more question. It is important for me to know for my exam
Michele_Laino
  • Michele_Laino
ok!
korosh23
  • korosh23
I open a new question
Michele_Laino
  • Michele_Laino
ok!

Looking for something else?

Not the answer you are looking for? Search for more explanations.