Finding accerlation in this problem

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The problem involves calculating the acceleration of a sled carrying a 16 kg child, pulled by two teenagers with a force of 53 N at a 35° angle, while facing a retarding force of 57 N from the snow. The initial equation used to find acceleration was incorrect due to two main errors: the total mass should be calculated as the sum of the child and sled, and the pulling force should account for both teenagers. The correct approach involves using the total mass in the equation and adjusting the forces accordingly. After correcting these mistakes, the proper formula can be applied to find the sled's acceleration. Accurate calculations are essential for determining the correct acceleration in this scenario.
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To give a 16 kg child a ride, two teenagers pull on a 3.4 kg sled with ropes, as indicated in Figure 5-26. Both teenagers pull with a force of F = 53 N at an angle of 35° relative to the forward direction, which is the direction of motion. In addition, the snow exerts a retarding force on the sled that points opposite to the direction of motion, and has a magnitude of 57 N. Find the acceleration of the sled and child.

picture: http://i232.photobucket.com/albums/ee319/reddevilzofah/05-23alt.gif

Okay, I've tried to solve this problem and I added all the Fx. So I did 16+3.4a=-53cos35+57 Solved for a, but the answer was wrong. Can someone tell me what I did wrong and how to fix it?

Thanks!
 
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Could you please show us each step of your work, so we can look for where you might have made a mistake?
 
16+3.4a=-53cos35+57 and solved for a. Thats that work. Is the equatio wrong?
 
keweezz said:
16+3.4a=-53cos35+57 and solved for a. Thats that work. Is the equatio wrong?
Two mistakes:
(1) The total mass is 16 + 3.4. So the left side should have parentheses: (16 +3.4)a.
(2) There are two teenagers pulling, not just one.
 
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