Answer to Question #190802 in Mechanics | Relativity for Lala

Question

Now imagine that one cart is oriented perfectly in-line with the string, but the other cart is skewed so that there is an angle, θ, between the direction that the string was pulling and the direction the force sensor can measure.

(a) Would the force sensor on the angled cart read higher or lower?

Answer 1

The situation of this problem will look like this,

The thread is pulling both the carts same time with a fixed tension at the moment & the force sensors are set up on each cart which measure forces act perpendicular to a cart. Therefore, the blue cart measures the force imposed on it by the thread which is exactly its tension, as the cart (the force sensor more precisely) is in-line with the thread while the green one measures only the tension's component perpendicular to it (along the dotted blue line).

As both the carts start to move blue one continues straight with the thread while the green one adjusts its orientation to an in-line position before moving which gradually reduces the difference between the measurements from the sensors of the 2 carts.