Answer:
The ball takes 5s to reach the ground
Explanation:
in order to solve this problem we use the kinematics equation with gravity as acceleration:

we replace the values

We solve this quadratic equation:
t=5s
t=-6s (this solution has not physical sense)
<h2>
Kinetic energy of mass 4 kg ball is less than kinetic energy of mass 2 kg ball</h2>
Explanation:
Kinetic energy = 0.5 x Mass x Velocity²
For ball of mass 2 kg
Mass, m = 2 kg
Velocity, v = 4 m/s
Kinetic energy = 0.5 x 2 x 4² = 16 J
For ball of mass 4 kg
Mass, m = 4 kg
Velocity, v = 2 m/s
Kinetic energy = 0.5 x 4 x 2² = 8 J
Kinetic energy of mass 4 kg ball is less than kinetic energy of mass 2 kg ball
Answer:
Without units, the results are unclear and it is hard to keep track of what each seperate measurement entails.