Final answer:
The minimum initial speed required for an athlete to jump over a 5.7 m wide river at a 35-degree angle can be calculated using the kinematic equation for projectile motion, taking into account gravity and the width of the river.
Step-by-step explanation:
The student has asked a physics-related question about projectile motion. To determine the minimal initial speed that would allow an athlete to jump over a river 5.7 m wide at a 35-degree angle, we use the kinematic equations for projectile motion. The horizontal distance covered by a projectile (the range) is given by R = (v^2 sin(2θ)) / g, where v is the initial velocity, θ is the launch angle, and g is the acceleration due to gravity (9.81 m/s2). Solving for v, we find that v = √((R × g) / sin(2θ)). Therefore, the minimum initial speed needed can be calculated using the given parameters of the river width and the launch angle.