How Long Did the Power Delivery to the Ball Last?

AI Thread Summary
The discussion focuses on calculating the kinetic energy and power delivery time for a 5 kg ball tossed at an initial velocity of 6 m/s. The kinetic energy is determined to be 90 joules using the formula K.E = 1/2 mV^2. The power delivered to the ball is calculated as 0.9 seconds using the equation P = E/t, where P is 100 watts. There is some confusion regarding whether the initial velocity can be used directly in the kinetic energy equation, which is clarified that it can. Overall, the participants confirm the calculations and express a desire for further understanding of kinetic energy and power concepts.
pinnacleprouk
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Thanks in advance, I just want to double check!


Homework Statement



A 5 kg ball is tossed into the air with an initial velocity of 6m/s.
a) What is the kinetic energy of the ball?
b) If the power delivered to the ball was 100watts, over what time interval did
the power delivery occur?




Homework Equations



K.E = 1/2 mV*2

P = E/t



The Attempt at a Solution




a)... using K.E = 1/2 mV*2 answer is 90J

b)... using P = E/t answer is 0.9s
 
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Looks good!
 
But I am a bit confuesd, is initial velocity is equal to velocity in the equation?In other words, can we plug the value of initial v in v in the equation? Shouldn't we try to get velocity?
 
stanton said:
But I am a bit confuesd, is initial velocity is equal to velocity in the equation?In other words, can we plug the value of initial v in v in the equation? Shouldn't we try to get velocity?
The velocity is given. It's the velocity of the ball immediately after leaving the hand.
 
Thanks for the replies
 
Now I get it. :) Thanks! I am having difficulty with treating problems related to kinetic energy and power.
 

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