A racetrack curve has radius 70.0 m and is banked at an angle of 12.0 ∘. The coefficient of static friction between the tires an
d the roadway is 0.400. A race car with mass 1200 kg rounds the curve with the maximum speed to avoid skidding. consider friction when solving for a, b, and c.
a) As the car rounds the curve, what is the normal force exerted on it by the road?
b) What is the car's radial acceleration?
c) What is the car's speed?
d) In the case of a banked curve with friction, which of the following forces contribute to the centripetal (inward) acceleration: the frictional force, the normal force, and/or the gravity? and why?
a) As the car rounds the curve, what is the normal force exerted on it by the road?
b) What is the car's radial acceleration?
c) What is the car's speed?
d) In the case of a banked curve with friction, which of the following forces contribute to the centripetal (inward) acceleration: the frictional force, the normal force, and/or the gravity? and why?
1 answer:
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Answer:
a) See attached picture, b) We know the initial velocity = 0, initial position=0, time=12.0s, acceleration=, c) the car travels 172.8m in those 12 seconds, d) The car's final velocity is 28.8m/s
Explanation:
a) In order to draw a sketch of the situation, I must include the data I know, the data I would like to know and a drawing of the car including the direction of the movement and its acceleration, just like in the attached picture.
b) From the information given by the problem I know:
initial velocity =0
acceleration =
time = 12.0 s
initial position = 0
c)
unknown:
displacement.
in order to choose the appropriate equation, I must take the knowns and the unknown and look for a formula I can use to solve for the unknown. I know the initial velocity, initial position, time, acceleration and I want to find out the displacement. The formula that contains all this data is the following:
Once I got the equation I need to find the displacement, I can plug the known values in, like this:
after cancelling the pertinent units, I get that my answer will be given in meters. So I get:
which solves to:
So the displacement of the car in 12 seconds is 172.8m, which makes sense taking into account that it will be accelerating for 12 seconds and each second its velocity will increase by 2.4m/s.
d) So, like the previous part of the problem, I know the initial position of the car, the time it travels, the initial velocity and its acceleration. Now I also know what its final position is, so we have more than enough information to find this answer out.
I need to find the final velocity, so I need to use an equation that will use some or all of the known data and the unknown. In order to solve this problem, I can use the following equation:
Next, since I need to find the final velocity, I can solve the equation just for that, I can start by multiplying both sides by t so I get:
and finally I can add to both sides so I get:
and now I can proceed and substitute the known values:
which solves to:
