Yeah, hand signals are important in officiating games. The hand signals are given by the referee who first signals the fault and then indicates which team has won the point. A point is indicated by one finger at the side of the court to indicate the winner of the rally.
I think the correct answer from the choices listed above is the second option. For endothermic reactions, the reactants have less energy than the products. Which would mean that energy should be added to the reaction for it to proceed. Hope this answers the question.
<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>
The centripetal acceleration is responsible
for the artificial gravity because the acceleration of an object moving in constant
circular motion causing from net external force is called centripetal
acceleration. It defines to the center or seeking the center.
Given the following:
Cylindrical space station
diameter = 275 meters; 137.5
meters for the radius
Standard gravity =
9.80665 m/s²
Using the formula:
w² x r =g
w² = g / r
w² = 9.80665 m/s²
/ 137.5 m
w² = 9.80665 m/s²
/ 137.5 m
w² = 0.0713 s²
Then take the roots
w = 0.267 this is radians per
second / 2 x (3.1416 which is the pi)
w = 0.0424 rps convert to rpm
w = 0.0424 r/s (1minute / 60
seconds)
w = 7.08 x 10⁻⁴ revolutions per minute
If you are pushing the coin across the table at a constant rate, the friction of the table and the horizontal force of your hand pushing are equal, and the coin itself moves at a constant rate. If you push a coin and let it go, there is no horizontal force keeping the coin going. Friction slows the coin to a stop. In both cases, the gravitational downward pull of Earth is equally but oppositely resisted by the upward push of table on the coin.
