Answer:
t = 5.4 s
Explanation:
from the question we are given :
height (s) = 20 m
mass of paint (Mp) = 4 kg
mass of nails (Mn) = 3 kg
acceleration due to gravity (g) = 9.8 m/s^{2}
- The net force accelerating the can of paint should be equal to the difference in weight of the can of paint and the can of nails.
weight of nails = mass of nails x g = 3 x 9.8 = 29.4 N
weight of paint = mass nails x g = 4 x 9.8 = 39.2 N
net force = 39.2 - 29.4 = 9.8 N
- net force = total mass x acceleration
9.8 = (3 +4) x a
a = 1.4 m/s^{2}
- from S = Ut + 0.5at^{2} we can get the time the carpenter has to catch the nails
where U is the initial velocity and is 0 since the can was initially at
rest
20 = (0 x t) + (0.5 x 1.4 x t^{2})
20 = 0.7 x t^{2}
t^{2} = 28.6
t = 5.4 s
