Posted by senko on Monday, October 8, 2012 at 1:26pm.
A car starts from rest on a curve with a radius of 110m and accelerates at 1.2m/s^2. Through what angle will the car have traveled when the magnitude of its total acceleration is 2.1 m/s^2?
I thought i got the answer which was 0.75 rad or 43 degrees but it says its the wrong answer or the rounding is wrong. Please help!!!
Steps please.

Physics Circular motion  Elena, Monday, October 8, 2012 at 2:34pm
tangential acceleration is a(τ)= 1.2 m/s²
normal acceleration is a(n) = ω²R,
whwre ω is the angular velocity.
a=2.2 m/s²
a² = a(τ)²+ a(n)² = a(τ)²+ (ω²•R)²
ω⁴ = { a²a(τ)²)/R² =(2.1²1.2²)/110² = 2.45•10⁻⁴
ω=0.125 rad/s
The angular acceleration is
ε= a(τ)/R = 1.2/110 = 0.011 rad/s²
ω=ε•t => t=ω/ε
φ = ε•t²/2 = ε•ω²/2•ε²=ω²/2•ε =
=0.125²/2•0.011 = 0.71 rad.