A boy throws a ball vertically upwards from a bridge with velocity 5 ~m / s . It strikes water surface after 2 s . The height of the bridge is ( . Take .g=10 ~m / s ^2 )

Step-by-step solution

The height of the bridge is determined using kinematic equations with upward defined as positive. The ball's initial velocity is u = +5 , m/s , the time until impact is t = 2 , s , and acceleration due to gravity is a = -10 , m/s ^2 . The displacement equation s = ut + 1 2 at^2 applies, where s = -h represents the downward displacement from the bridge to the water surface. Substituting the values: -h = (5)(2) + 1 2 (-10)(2)^2 = 10 - 20 = -10 Solving yields h = 10 , m . The height of the bridge is 10 meters .