- #1
ooccoo
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Homework Statement
A car is being driven around in circles. The radius of the circle being made is R = 150.0 m. At t = 0, the car is on the left edge of the circle (therefore it is in the −x direction away from the center of
the circle if your origin is placed at the center), and it is moving in the +y direction. The initial speed is 12.0 m/s. However,
it is speeding up, with dv/dt = 1.00 m/s^2.
(a) What are the values of the displacement, velocity, and acceleration at t = 0?
(b) At time t = 10.83 s, it is now directly in the +y direction from the center of the
circle. What are the values of the displacement, velocity and acceleration?
(c) What was the average acceleration between t = 0 and t = 10.83 s?
(d) What is the value of t when you return to the position where you started?
Homework Equations
a=(dv/dt)(v-hat) - (v^2/R)(r-hat)
the hats are a function of where you are, and always point in different directions
and I believe a-hat would = a(vector) / |a (vector)| <<Absolute value... like magnitude.
The Attempt at a Solution
For a.) I believe that displacement would be 0 since the car hasn't moved. Velocity would be 12m/s in the +y direction, and acceleration would be 1.00 m/s^2 since acceleration is the derivative of velocity
For B, I start to get lost. I believe that I need to use the equation: [a=(dv/dt)(v-hat) - (v^2/R)(r-hat)]
I know that velocity is tangent to the circle and if the speed was constant, the acceleration would point directly at the center of the circle(making this problem easier) but instead it is point slightly forward
but I am getting thrown off by the fact that we're given the amount of time that has passed and the distance traveled (a fourth of the circumference)
any help would be greatly appreciated, my semester is almost over and I really want to understand this stuff before i go home for winter break. Thank you for your time!