Answer:
t = 3 t₀
Explanation:
The formula for the power delivered by the engine can be given in terms of the change in the potential energy of the box as follows:
P = P.E/t = mgy/t
where,
P = Power delivered by the engine
m = mass of box lifted = m₀
g = acceleration due to gravity
y = vertical distance or height box covered = y₀
t = time taken = t₀
Therefore,
P = m₀gy₀/t₀
t₀ = m₀gy₀/P -------------- equation (1)
Now, if we change the mass of box as:
m = 3m₀
y = y₀ (constant)
P = Constant
Then,
P = 3m₀gy₀/t
t = 3m₀gy₀/P
using equation (1):
t = 3 t₀