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[Phy] Physics Question (Force) Help

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Physics Question (Force) Help

1.
Tom sits in a carton a smooth surface which is inclined to the horizontal at an angle of 10° as shown (in the document below). The cart is tied with a rope which passes over a smooth pulley. The masses of Tom and the cart are 40 kg and 20 kg respectively. When Tom pulls the rope, he and the cart accelerate together at 0.5 m s
[suptag]-2[/suptag] up the surface. The two portions of the rope are parallel to the surface. Find the tension in the rope.




A     36.1 N


B     66.1 N


C     72.2 N


D     132 N


[ 本帖最後由 Hin2000 於 2016-7-26 12:25 PM 編輯 ]
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TOP

The following method is a bit advanced, a bit only
Please consider Tom and the cart as the same object, then
2T-(40+20)g(sin 10°)= (40+20)(0.5)
T=66.1 N

Am I correct?


[ 本帖最後由 Pockhin 於 2016-7-26 12:39 PM 編輯 ]
6科5**
http://lsforum.net/board/viewthread.php?tid=273337

TOP

yes . .

TOP

thx a lot   understand now

TOP

Considering two or more objects as a whole object is quite useful, but please make sure you really understand this method, otherwise, you may get a wrong answer frequently.

I suggest you calculate this question with the conventional method ( try to draw the free-body diagram of the cart and Tom.
It helps you to improve.



TOP

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