Answer:
v = 5.42 [m/s]
Step-by-step explanation:
To solve this problem we have to use the concept of energy transformation which tells us that kinetic energy is transformed into potential energy and vice versa.
The potential energy can be defined by means of the following equation.
Ep = m*g*h
where:
m = mass = 0.4 [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 1.5 [m]
Ep = 0.4*9.81*1.5
Ep = 5.88 [J]
Since the potential energy is equal to the kinetic energy, we can find the velocity by means of the kinetic energy equation.
Ek = 0.5*m*v²
where:
Ek = kinetic energy = 5.88 [J]
5.88 = 0.5*0.4*v²
v = 5.42 [m/s]