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Physics help please (dynamics)?
A mass (3kg) is hanging by a string. The other end of the string is accelerated horizontally (acceleration="a"); when this occurs, the string forms a 34 degree angle from the vertical. How do i find "a"?
1 Answer
- simplicitusLv 71 decade agoFavorite Answer
Cute.
In the steady state, there are two forces acting on the mass: gravity and the tension of the string.
Since the object is not moving vertically, the net vertical force must be 0.
That means that the vertical component of the tension on the string must equal the weight of the mass.
The horizontal component of the tension is determined by the total tension and the geometry.
Tv = T cos @
Th = T sin @
so Th = (Tv / cos @) sin @ = Tv tan @
You know that Tv = Mg so Th = M g tan @
You know force = mass x acceleration so
acceleration = force / mass = M g tan @ / M or
acceleration = g tan @