: To determine the focal length of a lens, the following except _ is needed
1 answer:
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Answer:
The rock has an impact speed of 9.9 m/s.
Explanation:
given information:
object's mass, m = 3 kg
height, h = 5 m
in this case, the potential energy is equal to the kinetic energy
PE = KE
mgh = mv²
where
m = mass (kg)
g = gravitational constant (9.8 m/s²)
v = velocity (m/s)
so,
mgh = mv²
gh = v²
v² = 2gh
v = √2gh
= √(2)(9.8)(5)
= 9.9 m/s