A ball thrown horizontally at 18m/s from a buliding's roof lands on a stray cat 25 m away from the base of the buliding. How high is the buliding?
To solve this problem, we can use the equations of motion for projectile motion.
First, we can find the time it takes for the ball to reach the stray cat by using the horizontal distance formula:
Horizontal distance = horizontal velocity * time
25m = 18m/s * time
time = 25m / 18m/s = 1.39s
Next, we can find the height of the building by using the vertical distance formula:
Vertical distance = initial vertical velocity * time + (1/2) * acceleration * time^2
Since the ball was thrown horizontally, the initial vertical velocity is 0. The acceleration due to gravity is -9.8m/s^2 (negative because it acts in the opposite direction to the motion of the ball).
Vertical distance = 0 * 1.39s + (1/2) * (-9.8m/s^2) * (1.39s)^2
Vertical distance = -6.8m
Therefore, the height of the building is 6.8m.