Answer
t = 367.77 s = 6.13 min
Explanation:
According to the law of conservation of energy:
where,
P = Electric Power of Heater = 300 W
t = time required = ?
m_g = mass of glass = 300 g = 0.3 kg
m_w = mass of water = 250 g = 0.25 kg
C_g = speicific heat of glass = 840 J/kg.°C
C_w = specific heatof water = 4184 J/kg.°C
ΔT_g = ΔT_w = Change in Temperature of Glass and water = 100°C - 15°C
ΔT_g = ΔT_w = 85°C
Therefore,
<u>t = 367.77 s = 6.13 min</u>
We are given that a 500 kg object is hanging from a spring. To determine the amount the spring is stretched we will use Hook's law, which states the following:
Where:
Since the object is hanging the only force acting on the spring is the weight of the object. The weight of the object is:
Where:
Plugging in the values we get:
Solving the operations:
Now we solve for "x" from Hook's law by dividing both sides by "k":
Now we plug in the known values:
Solving the operations:
Therefore, the spring is stretched by 5.4 meters.