Question

A pair of fuzzy dice is hanging by a string from your rearview mirror. while you are accelerating from a stoplight to 28 m/s in 6.0 s, what angle does the string make with the vertical? (assume your acceleration is constant.)

Answer 1

We can use the formula of motion in physics (2nd law od newton) in this problem:
x direction: Fsin ∅ = ma 
y direction: Fcos ∅ -mg = 0
∅ is equal to sin ∅ / cos ∅  or x/y
tan ∅ = ma / mg = a /g

Applying acceleration formula:
v = vo + at ; 28 = 0 + 6a ; a = 4.67 m/s^2
∅ = tan-1 (a/g) = tan-1 (4.67/9.81) = 25.4 degrees.