Một Con Lắc đơn Chiều Dài L = 2 M. Kéo Con Lắc Lệch Khỏi Vị Trí Cân ...

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Câu hỏi

Một con lắc đơn chiều dài l = 2 m. Kéo con lắc lệch khỏi vị trí cân bằng một góc 60° rồi thả nhẹ. Bỏ qua ma sát, lấy g = 10 m/s2. Vận tốc của vật khi nó qua vị trí cân bằng có độ lớn là:

A.

m/s.

B.

10 m/s.

C.

m/s.

D.

5 m/s.

Đáp án và lời giải Đáp án:A Lời giải:

m/s.

- Ta có biểu thức của vận tốc ở li độ góc α là:

v = ±.

Theo đầu bài α0 = 60°, khi vật đi qua vị trí cân bằng thì li độ góc α = 0°. Thay α0 = 60° và α = 0° vào biểu thức của vận tốc, ta được:

v = ±.

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