The average speed of the car for the entire trip can be calculate by using:
where S is the total distance covered by the car, and t is the total time taken.
The total distance travelled by the car is:
while the total time taken is:
so, the average speed of the car is:
so, the correct answer is (3) 85 km/h.
Explanation:
At point B, the velocity speed of the train is as follows.
=
= 26.34 m/s
Now, we will calculate the first derivative of the equation of train.
y =
Now, second derivative of the train is calculated as follows.
Radius of curvature of the train is as follows.
=
= 3808.96 m
Now, we will calculate the normal component of the train as follows.
=
= 0.1822
The magnitude of acceleration of train is calculated as follows.
a =
=
=
Thus, we can conclude that magnitude of the acceleration of the train when it reaches point B, where sAB = 412 m is .