How do i do that though
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I don't understand
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Your picture is not showing and i don't understand most statements in physics could you give me a formula or something which i could use
(edited 7 years ago)
Original post by Hollybollybee109
Set potential energy (mgh) equal to kinetic energy (1/2mv^2) and rearrange for v.
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If you mean to do this is doesnt give the right answer
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Original post by Hollybollybee109
Also btw for future reference the masses cancel out so it should actually be v=sqrt2xgh
It gives the same wrong answer... I need help
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Original post by Hollybollybee109
Is the answer 22. Something?
For a the answer is 18.8 and for b the answer is 9.9
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This is what I got. Hope it's right and I didn't waste my time lol.
Ignore it's wrong I didn't see that it started off at 12 m/s.
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Ignore it's wrong I didn't see that it started off at 12 m/s.
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(edited 7 years ago)
My teacher gave me the answers so maybe she got it wrong, thank you for your help
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Original post by Hollybollybee109
My teacher gave me the answers so maybe she got it wrong, thank you for your help
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I think 22.3 is correct, both my friends who studied mechanics and I (who did a level physics) got the same results. Please do update me im really curious as how the answer is 18 x
Original post by Hollybollybee109
My teacher gave me the answers so maybe she got it wrong, thank you for your help
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Yeah I have no idea how to do it, sorry. I tried using momentum, energy equations and kinematics.
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--
(edited 7 years ago)
Original post by Hollybollybee109
I think I may know how your teacher arrives the "answer" of 18.8 m/s at Y.
I suggest that you attempt to understand the statements in physics instead of just the formula or equations to use.
Using conservation of energy and consider roller-coaster and Earth as the system.
PE at X + KE at X = PE at Y + KE at Y
---(1)
It can be simplified to
---(2)
If equation (2) is used, the answer would 22.3 m/s as shown below:
Your teacher's answer did not consider the speed at X. If the speed at X is zero, we would arrive 18.8 m/s for the speed at Y using equation (2) as shown below:
Attachment not found
But the question stated that the speed at X is 12 m/s, so your teacher answer is incorrect.
Similarly, we would arrive the speed at Z to be 9.9 m/s using equation (2) and consider the speed at X to be zero. Test it yourself.
It may be good that you inform your teacher privately.
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