Calculating Maximum Height in Projectile Motion on a Trampoline

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Homework Help Overview

The discussion revolves around calculating the maximum height achieved when jumping off a trampoline with an initial velocity of 30 km/h. The subject area is projectile motion, specifically focusing on vertical motion under the influence of gravity.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need to convert units from km/h to m/s for consistency with gravitational acceleration. There are attempts to apply kinematic equations, with some participants questioning their calculations and the assumptions made regarding units.

Discussion Status

The discussion is ongoing, with participants providing insights into unit conversions and the application of equations. Some have shared their calculations and results, while others have raised questions about the correctness of these approaches. There is no explicit consensus on the correct method or final answer yet.

Contextual Notes

Participants are navigating the challenge of ensuring unit consistency in their calculations, particularly between velocity and acceleration units. There is also a mention of a specific answer in meters, which has prompted further discussion on the necessary conversions.

pennywise1234
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Homework Statement


You jump straight upward off a trampoline with an initial velocity of 30 km/h. How high above the trampoline will you reach?

Homework Equations


v2=v1 + a x t & v2(square root)=v1(square root) + 2ad

The Attempt at a Solution


I tried 30km/h into the second equation (knowing that acceleration in 9.81) and that the vertical at its peak is 0 but my number is no were near the answer key

do i have to convert km/h to m? and where did i go wrong
 
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pennywise1234 said:

Homework Statement


You jump straight upward off a trampoline with an initial velocity of 30 km/h. How high above the trampoline will you reach?

Homework Equations


v2=v1 + a x t & v2(square root)=v1(square root) + 2ad

The Attempt at a Solution


I tried 30km/h into the second equation (knowing that acceleration in 9.81) and that the vertical at its peak is 0 but my number is no were near the answer key

do i have to convert km/h to m? and where did i go wrong
How can we tell where you went wrong when you don't show your work? You could be making a simple math error.
 
i did v2=0 v1=30km/hr + 2 x 9.81 (d)
i square rooted 30 to get 900 + 2 x 9.81 to get 919.62 which is far off from the answer i need
 
to answer your other question, you have to make sure all your units agree. Km/h is not the same as m/s^2 (which is what the acceleration due to gravity is in, I am assuming). Units of length must agree and units of time must agree.
 
the answer is in meters, which is 3.54m. So i do not convert km to m i convert to degrees?
 
pennywise1234 said:
the answer is in meters, which is 3.54m. So i do not convert km to m i convert to degrees?
Convert km/h into the same units as your acceleration - so if using 9.81m/s2 convert km/h into m/s. You are only dealing with one direction so there isn't a reason to apply any conversion of degrees.
 
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thanks i did D= v2 - V1/2 X a

so i did 0-8.3 (Square root)/2 x 9.81

then i did 68.8/19.62 got 3.51m

does that seem right ^^
 

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