Find the gravitational potential energy

AI Thread Summary
To find the gravitational potential energy of a child on a swing at a 34.7-degree angle, the equation PE = mgh is used, where m is the mass, g is the acceleration due to gravity (9.81 m/s^2), and h is the height above the lowest position. The height h is determined using trigonometry, calculated as h = 2.16 m * sin(34.7°), resulting in h = 1.23 m. Substituting the values into the equation gives PE = (41.7 kg)(9.81 m/s^2)(1.23 m), resulting in a gravitational potential energy of 509.5 joules. This calculation illustrates how to apply both the potential energy formula and trigonometric principles to solve the problem. The final answer for the gravitational potential energy is 509.5 joules.
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Given: g=9.81 m/s^2.
A 41.7 kg child is in a swing that is attached to robes 2.16 m long. Find the gravitational potiental energy associated with the child relative to the child's lowest position under the following conditions:
B. when the ropes make a 34.7 degree angle with the vertical.

What equation would I use?
 
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Well, potential energy = mgh looks good!

You might also want to draw a picture and use a little trigonometry to determine exactly what h is when the swing makes an angle of 34.7 degrees with the vertical.
 


To find the gravitational potential energy of the child in this scenario, you would use the equation PE = mgh, where m is the mass of the child, g is the acceleration due to gravity (given as 9.81 m/s^2), and h is the height of the child above their lowest position. In this case, h would be equal to the vertical component of the ropes, which can be found using trigonometry as h = 2.16sin(34.7) = 1.23 m.

Plugging in the values, we get PE = (41.7 kg)(9.81 m/s^2)(1.23 m) = 509.5 J. Therefore, the gravitational potential energy associated with the child in this scenario is 509.5 joules.
 
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