Compute the total force which shall be acting on the springs:
An automobile of mass 1300 kg, travelling at a speed of 60 kmph hits a depression in the road that has a radius of curvature of 15 m. Compute the total force which shall be acting on the springs.
Solution
The speed of the car is 60 kmph, i.e.
(60 × 1000)/3600
= 16.67 m / sec
The car is travelling along with a curve of radius 15 m. Hence, acceleration
a_{n} = v^{2} / r .
∴ a_{n} = (16.67)^{2}/ 15
= 18.52 m / sec
The inertia force F_{i }= - m a_{n} shall be acting as illustrated.
∴ F_{i } = - m . a_{n }= 1300 × 18.52
= 24076 N
Considering equilibrium of forces as illustrated in Figure (b), we obtain following
∑ Fy = 0 ∴ N = F_{i} + mg
= 24076 + 12753 = 36829 N ;
where mg = 1300 × 9.81