A ball is projected horizontally from the top of a hill with a velocity of 20m-1. If it reaches the ground 4 seconds later, what is the height of the hill? ...

Answer Details

We can solve this problem using the kinematic equations of motion. Since the ball is projected horizontally, its initial vertical velocity is zero. We can use the following equation to find the height of the hill: h = (1/2)gt^2 Where h is the height of the hill, g is the acceleration due to gravity, and t is the time taken for the ball to reach the ground. In this case, g = 10ms^-2 and t = 4s. Plugging these values into the equation, we get: h = (1/2)(10)(4)^2 = 80m Therefore, the height of the hill is 80 meters. This is option (C). To summarize, the ball is projected horizontally with a velocity of 20m/s, which means its initial vertical velocity is zero. Using the kinematic equation for displacement, we can find the height of the hill. The ball takes 4 seconds to reach the ground, so we substitute this value along with the acceleration due to gravity into the equation. The resulting answer is 80 meters, which is the height of the hill.