Calculating Velocity and Time of a Falling Object from a Given Height

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To calculate the speed of the rock when it hits the ground, the final velocity can be determined using the formula v = u + at, where u is the initial velocity (18 m/s), a is the acceleration due to gravity (approximately 9.81 m/s²), and t is the time taken to fall. The time to hit the ground can be calculated using the formula h = ut + 0.5at², where h is the height (52 meters). The calculations yield a final speed of approximately 31.45 m/s and a time of about 1.4 seconds for the rock to reach the ground. It's important to follow the homework template for clarity in future discussions. Accurate calculations are essential for understanding the physics of falling objects.
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Jen is standing on top of a 52 meter high building. She threw a rock straight downward at 18m/s.
How fast will the rock be traveling when it hits the ground?
Determine how long it will take for the ball to hit the ground?

my attempt: I got 31.45m/s as the speed of the rock and 1.402 seconds to hit the ground, but I don't think I did it right. Can someone please help me out?
 
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