OK thank you :)

Hi I got this way for answer what do you say?

(my teacher gave me this way)

http://p1cture.me/images/81707901136255067694.jpg
http://p1cture.me/images/39708482776376761480.jpg
I would like to know what you think. :)

Thanks.

Well, if you work out the first calculation... do you get 4320 kJ? I'm still getting 1080 kJ

I think your teacher took the 1/2 term in front of the kinetic energy calculation and accidentally multiplied by 2, instead of dividing by 2.

You should point out to him that if you fired an object from a canon straight up into the air, it would have to be traveling almost 200 km/h to attain a height of 150m. Logic should tell you that an object slowing from 100 km/h to 50 km/h is certainly not going to climb anywhere near that much altitude!

OK I will as her.
If both of you tell there a mistake so I think there a mistake :)

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