Answer:
10.5min
Explanation:
Given parameters:
Distance = 4200m
Speed = 400m/min
Unknown:
Time taken for this run = ?
Solution:
Speed is the distance divided by the time taken.
Speed = 
Time = 
Now insert the parameters and solve;
Time = 
= 10.5min
<span>Answer:
For Lewis theory, the most stable species will have a complete octet for as many atoms as possible. Construct Lewis dot structures for each species. You should see that CN+ cannot give a complete octet to the C atom unless a quadruple bond - unknown except in transition metals - is formed. CN will have an odd number of electrons, and is thus a free radical and unstable with respect to dimerization (it forms cyanogen). CN-, the familiar cyanide ion, gives both C and N a complete octet with a triple bond, and is thus the most stable.
Molecular orbital theory is a bit more complex. Nitrogen and carbon are close enough in electronegativity, so the orbitals from the C atom will mix with the same orbitals from the N atom. The molecular orbitals formed will be sigma2s, sigma*2s, pi2p, sigma2p, pi*2p, and sigma*2p. The * denotes an antibonding orbital; these are higher in energy, and electrons placed into these orbitals weaken the bonding between two atoms. CN+ will completely fill the sigma2s, sigma*2s, and pi2p orbitals. CN will add an electron in the bonding sigma2p orbital, and the atoms are thus more strongly bonded than in CN+. CN- fills the sigma2p orbital, and the addition of another bonding electron means that this species has the strongest bond of the three. I might have the names of some of the filled levels incorrect; the energy levels of the sigma2p and pi2p swap at some point. This concept is hard to explain without a picture; see the link.
Thus, both MO and Lewis theory predict CN- as the most stable species, a prediction that matches well with experimental data.</span>
Answer:
The actual work output is 1,125 kilojoules.
Explanation:
Energy efficiency is defined as the efficient use of energy. An appliance, process, or facility is energy efficient when it consumes less than the average amount of energy to perform an activity. Then, energy efficiency is the ratio between the amount of energy used in an activity and the amount expected to be carried out.
Efficiency is calculated as:
efficiency = output / input
Where output is the amount of mechanical work (in watts) or energy consumed by the process (in joules), and input (input) is the amount of work or energy that is used as input to carry out the process.
In this case:
- Efficiency always has a value between 0 and 1. In this case, efficiency=0.15
- output=?
- input= 7500 kilojoules
Replacing:
0.15=output/7500 kilojoules
Solving:
Output=0.15* 7500 kilojoules
output=1,125 kilojoules
<u><em>The actual work output is 1,125 kilojoules.</em></u>
Answer:
449.38 J
Explanation:
ΔS = ΔQ/T
Where ΔS = entropy change
Q = quantity of heat
T = temperature
First reservoir :
T = –30°C = - 30 + 273 = 243K
Q = 400 J
Second reservoir :
T = 0°C = 273K
Q =?
To have same increase in entropy for both reservoirs :
Q/T of first reservoir = Q/T of second reservoir
400/243 = Q/273
243 * Q = 400 * 273
Q = (400 * 273) / 243
Q = 109,200 / 243
Q = 449.38271
Q = 449.38 J
Answer:
j
Explanation:
x = 4 t^2 - 2 t - 4.5
Position at t = 3 s
x = 4 (3)^2 - 2 (3) - 4.5 = 25.5 m
Velocity at t = 3 s
v = dx / dt = 8 t - 2
v ( t = 3 s) = 8 x 3 - 2 = 22 m/s
Acceleration at t = 3 s
a = dv / dt = 8
a ( t = 3 s ) = 8 m/s^2
When is the velocity = 0
v = 0
8 t - 2 = 0
t = 0.25 second
When is the position = 0
x = 0
4 t^2 - 2 t - 4.5 = 0
t = 1.4 second
