F.4 Phy mechanics

fgsfd

2014-01-23 6:06 am

A block of mass m is placed on an smooth inclined plane.The plane makes an
angle of 26.6 to the horizontal.If the horizontal force F required to keep the block
from sliding down is 0.5mg,what is the force N between
the block and the plane?

回答 (1)

用戶4366

2014-01-23 7:05 am

✔ 最佳答案

圖片參考：http://imgcld.yimg.com/8/n/HA00388954/o/20140122230059.jpg

Since F1 - F2 is not zero, the block should move. If the block does not move, this force must be balanced by a friction exactly of this size. This is the force between the block and the plane.

如圖太細，可把滑鼠移至圖上，按右鍵，另存圖片到電腦上(例如桌面)，再在電腦上開啓，便會放大了。

2014-01-22 23:40:34 補充：
我可能誤解了題目，[ A block of mass m is placed on an smooth inclined plane. ] 應該沒有 friction.

題目所問的可能是 normal force 的大小。

normal force = mgcosθ + 0.5mgsinθ

= mg(cosθ + 0.5sinθ)

=10.96m Newton

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