Question

3. Same questions as the previous problem, but for mass m just falling 3 meters in a vacuum: (a) How long does it take mass m to fall 3 meters? (b) What is its final velocity (with direction)? (c) Explain what physics principle makes (b) be the same or different in problems (2) and (3).

Answer 1

a) 0.78 s

b) 58.86m/s'

c) Galileo's law of free fall

Step-by-step explanation:

a)
`x = v_(i)t + (1)/(2)at^(2) \\3 = 0*t+(1)/(2) *9.81*t^(2)\\t=\sqrt{(6)/(9.81) }`

b)At the bottom:

kinetic energy = potential energy

`(1)/(2)mv^(2) = mgh\\ v^(2) =2*9.81*3=58.86m/s` downwards

c) Galileo's law of free fall says regardless of the masses, bodies in a vacuum will fall, on the earth, at the same acceleration