ALWAYS use significant figure rules. Remember that these rules apply to all numbers that are measurements.
An object is dropped from a platform 400 ft high. Ignoring wind resistance, what will its speed be when it reaches the ground?
12,800 ft/s
7800 ft/s
160 ft/s
89 ft/s
V^2 = Vo^2+2g*h = 0+64*400 = 25,600
V =
To determine the speed at which the object will hit the ground, we can use the kinematic equation:
v = √(2gh)
Where:
v = speed (in ft/s)
g = acceleration due to gravity (32 ft/s² approximately)
h = height (in ft)
In this case, the height (h) is given as 400 ft. Substituting these values into the equation:
v = √(2 * 32 ft/s² * 400 ft)
First, we can evaluate the expression inside the square root:
2 * 32 ft/s² * 400 ft = 25,600 ft²/s²
Taking the square root of this value:
√(25,600 ft²/s²) = 160 ft/s
Therefore, the speed of the object when it hits the ground is approximately 160 ft/s. Hence, the correct answer is 160 ft/s.
the platform height is one significant figure
all of the responses are at least two significant figures