Final answer:
Using the kinematic equations for an object under the influence of gravity, we find the velocity of the ball, as it appears at the top of the window after being dropped from the roof, to be 15.5 m/s, which is option (2).
Step-by-step explanation:
The question involves solving a problem related to the motion of a falling object under gravity, which is a fundamental concept in Physics. When a ball is dropped and crosses a window of height 1.5 m in 0.1 s, we can calculate its velocity at the top of the window by considering the equations of motion under the acceleration due to gravity (g).
To find the velocity at the top of the window (v), we can use the equation for distance (s) in terms of time (t), initial velocity (u), and acceleration (a):
s = ut + 1/2 at²
Assuming the ball starts at the top of the window with a speed of 0 m/s (since it was dropped), and taking the acceleration due to gravity as 10 m/s², the equation simplifies to
s = 1/2 gt²
After rearranging and solving for the final velocity (v) using the equation:
v² = u² + 2as
We can calculate the velocity of the ball at the topmost point of the window, which will be option (2) 15.5 m/s.