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I have been trying to work out this question for hours but it baffles me. It does say It can be calculated using the energy method or the linear motion method but I don't properly understand them.

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- #1

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I have been trying to work out this question for hours but it baffles me. It does say It can be calculated using the energy method or the linear motion method but I don't properly understand them.

- #2

Dale

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What is the formula for gravitational potential energy and the formula for work?

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PE = mgh and W = FdWhat is the formula for gravitational potential energy and the formula for work?

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Dale

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Oops. I meant the formula for gravitational PE and kinetic energy. Sorry.

- #5

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Kinetic energy is 1/2 m v2 but I don't have velocityOops. I meant the formula for gravitational PE and kinetic energy. Sorry.

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Dale

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Right, it is what you want to calculateKinetic energy is 1/2 m v2 but I don't have velocity

- #7

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So because GPE = 220725Right, it is what you want to calculate

v2 = 220725-1/2m?

- #8

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my calculations were 220725-½2250 = 219600squaredRight, it is what you want to calculate

root 219600 = 468.6 m/s2

I feel like I am doing something wrong.

- #9

jtbell

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Did you really mean to write 220725 minus 1/2m?v2 = 220725-1/2m?

Kinetic energy is 1/2m times v2, not 1/2m plus v2.

By the way, most people here will read 1/2m as "one divided by 2m", not "one-half m". Better to write it as (1/2)m or more simply m/2.

- #10

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I see what I have done, I got the right answer at last. Thanks for the help :)Did you really mean to write 220725 minus 1/2m?

Kinetic energy is 1/2m times v2, not 1/2m plus v2.

By the way, most people here will read 1/2m as "one divided by 2m", not "one-half m". Better to write it as (1/2)m or more simply m/2.

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jtbell

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- #12

Dale

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Where are you getting the ##-\frac 1 2 m##? Check your units. Does that make sense? Can you subtract mass from energy?So because GPE = 220725

v2 = 220725-1/2m?

Always include your units, what you have written is confusing and including units will reduce the confusion and avoid mistakes like this.

- #13

sophiecentaur

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Stick with the algebraic representation and re-arrangement until the very end and then substitute the numbers that you have. That way you will be able to solve any such question.my calculations were 220725-½2250 = 219600squared

root 219600 = 468.6 m/s2

I feel like I am doing something wrong.

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