<span>Melting of ice is an endothermic process, meaning that energy is absorbed. When ice spontaneously melts, ΔH (change in enthalpy) is "positive". ΔS (entropy change) is also positive, because, becoming a liquid, water molecules lose their fixed position in the ice crystal, and become more disorganized. ΔG (free energy of reaction) is negative when a reaction proceeds spontaneously, as it happens in this case. Ice spontaneously melts at temperatures higher than 0°C. However, liquid water also spontaneously freezes at temperatures below 0°C. Therefore the temperature is instrumental in determining which "melting" of ice, or "freezing" of water becomes spontaneous. The whole process is summarized in the Gibbs free energy equation:
ΔG = ΔH – TΔS</span>
Answer:
Explanation:
given,
J = 50 kg-m²
frequency, f = 20 Hz
time ,t = 5 s
we know,
angular velocity = 2 π f
ω = 2 π x 20
ω = 125.66 rad/s
now, angular acceleration calculation
α = 25.13 rad/s²
Torque given to the flywheel.
Torque of the given flywheel is equal to
Answer:
0.405 seconds
Explanation:
Consider the amount of time it takes the block to fall from 53 m up to 14 m above the ground; then consider the amount of time it takes the block to fall from 53 m up to 2 m above the ground.
First, d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 × 39 / 9.8)^1/2 = 2.8212 seconds
Then, to fall from 53 down to 2 meters...
d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 * 51/ 9.8 )^1/2 = 3.2262 seconds
So the amount of time it takes for the block to fall from 14 m upto 2 m above the ground
3.2262 - 2.8212 = 0.405 seconds
this is how much time there is from when the man sees the block until it hits him. Not much time...
