A car of mass m moves with a constant speed `upsilon` over (a) horizontal flat surface (b) convex bridge (c) concave bridge What force is exerted by the car on the bridge as it passes the middle point of bridge Radius of curvature of bridge is `R` .

Answer

`R_(1) = mg ; R_(2) mg` .

Explanation

`R_(1)` is just equal and opposite to weight of car
`R_(1) = mg`
bridge is convex
`mg - R_(2) = (m upsilon^(2))/(r) , R_(2) = mg - (m upsilon^(2))/(r) , R_(2) lt mg`
(c) bridge is concave
`R_(3) - mg = (m upsilon^(2))/(r), R_(3) = mg + (m upsilon^(2))/(r) , R_(3) gt mg`
.