Find an equation relating the rate of change of kinetic energy to the rate of change of velocity
1 answer:
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Answer:
Explanation:
To solve this problem we use the Hooke's Law:
(1)
F is the Force needed to expand or compress the spring by a distance Δx.
The spring stretches 0.2cm per Newton, in other words:
1N=k*0.2cm ⇒ k=1N/0.2cm=5N/cm
The force applied is due to the weight
We replace in (1):
We solve the equation for m:
Answer:
Explanation:
From the given information:
The initial PE = m×g×h
= 5 kg × 9.81 m/s² × 10 m
= 490.5 J
The change in Potential energy P.E of the box is:
ΔP.E =
ΔP.E = 0 -
ΔP.E =
If we take a look at conservation of total energy for determining the change in the internal energy of the box;
this can be re-written as:
Here, K.E = 0
Also, 70% goes into raising the internal energy for the box;
Thus,
ΔU = 343.35 J
Thus, the magnitude of the increase is = 343.35 J