Let me try:
Normal force= 169.74N
Coefficient of kinetic friction= 0.577
Explanation
a. For a given inclined plane, normal friction is equal to the force perpendicular to the plane which is equal to
mgcos theta = 20×9.8× cos30 = 169.74N
b. The coefficient of kinetic friction for an inclined plane is given as
tan theta =tan 30 = 0.577
The average speed of Frank's car is 2 m/s and the average speed of Noah's car is 1.8 m/s.
<u>Explanation:</u>
Average speed is the measure of total distance covered at different time period. Since, the formula used for calculating the average speed is the ratio of total distance covered by each car to the time taken to cover that distance.
As there is only one set of data i.e., distance and time, the average speed will be equal to the speed of the car.
So in this case, the total distance covered by franks car is 300 cm = 3 m in 1.5 s. Then, the average speed will be


Similarly, the average speed of Noahs car which rolled a distance of 360 cm = 3.6 m in time 2 s, will be

Thus, the average speed of Frank's car is 2 m/s and the average speed of Noah's car is 1.8 m/s.
B. The location of an object.
The term position describes the location of a place with respect to some reference point called origin.
To be able to determine the original speed of the car, we use kinematic equations to relate the acceleration, distance and the original speed of the car moving.
First, we manipulate the one of the kinematic equations
v^2 = v0^2 + 2 (a) (x) where v = 0 since the car stopped
Writing the equation in such a way that the initial velocity or v0 is written on one side of the equation,
<span>we get v0 = sqrt (2(a)(x))
Substituting the known values,
v0 = sqrt(2(3.50)(30.0))
v0 = 14.49 m/s
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Therefore, before stopping the car the original speed of the car would be 14.49 m/s