2. Block A (0.40 kg) and block B (0.30 kg) are on a frictionless table (see figure). Spring 1 connects block A to a frictionless peg at O and spring 2 connects block A and block B. When the blocks are in uniform circular motion about O, the springs have lengths of 0.60 m and 0.40 m, as shown. The springs are ideal and massless, and the linear speed of block B is 2.0 m/s. If the spring constant of spring 1 is equal to 30 N/m, the unstretched length of spring 1 is closest to
(A) 0.51 m,
(B)0.53 m,
(C) 0.55 m,
(D) 0.54 m,
(E) 0.52 m. 00000000003 0.60 m heQ00- -0.40 m-

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詳解 (共 3 筆)

#6995579
1. 題目解析 這道題目考察了物體在圓周...
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#6995581
1. 題目解析 在這道題目中,我們有兩個...
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#7407535
所以這題第一步要先求角速度
題目有給B的切線速度
所以可以用v=rw求出w
記得這裡的r是0.6+0.4
然後又因為a和b連著一起轉,所以w相同
最內側的F1提供a和b轉的向心力
所以木塊a和b的向心力用mrw平方來求
代入即可得到為2.16牛頓
然後再根據F=k×x的變化量
可以求出為拉長0.072
最後再用0.6去扣即為所求
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