The correct option is b i.e none is correct.
The instantaneous velocity would be zero at the top but the acceleration would not be zero at that point. This is because the acceleration is the rate of change of velocity. since, the velocity is not constant, hence the acceleration would not be zero. The correct answer would be option b: None is correct.
To be honest with you, there's not enough information here to calculate
the answer, because we don't know the power consumption of the front
porch light. The best we can do is represent that as a variable ... pick a
catchy name for it, which will show up in the final answer, and then you
can 'plug in' (get it ?) whatever size light bulb you want to use over the
front porch.
OK. First we have to give it a name. I could use a single letter, but
that's what everybody else always does. Remember ... this is going to
represent the power (watts) consumed by the front porch light when it's
turned on. It's the symbol that means "Front Porch Light Power" wherever
you see it. I could easily call it x or y or z, but I'm going to call it " FPLP ".
OK. FPLP = power consumption of the light, in watts .
0.001 FPLP = power consumption of the light, in kilowatts (kW).
(1 week) · (7 day/week) · (24 hour/day) = 168 hours .
Energy = (power) · (time) = (0.001 FPLP) · (168 hr) = 0.168 FPLP kWhours
Cost = ($0.17 per kWh) · (number of kWh) = (2.86¢) · (FPLP) .
There it is !
For an example, if you use a 100-W bulb in the front porch light,
then FPLP=100 W. If you leave it on 24/7 for a whole week, then
it's going to cost
(2.86¢) · (FPLP) = (2.86¢) · (100 W) = $2.86
Note: <em>The question states the time to go upstream is a number of times (not explicitly written) the time to go downstream. We'll assume a general number N</em>
Answer:
Explanation:
<u>Relative Speed</u>
If a boat is going upstream against the water current, the true speed of motion is 
, being 
the speed of the boat and 
the speed of the water. If the boat is going downstream, the true speed becomes 
.
The question states the time to go upstream is a number of times N (not explicitly written) the time to go downstream. The speed of an object is computed as
Where x is the distance traveled and t the time taken for that. The time can be computed by
If 
is the time for the upstream travel and 
is the time for the downstream travel, then
Siince the same distance x= 10 miles is traveled in both cases:
Simplifying and rearrangling
Operating
Solving for
If N=3
We can use the required value of N to compute the speed of the boat as explained
Answer:
Explanation:
Total internal reflections is a phenomenon where incident light rays when travelling from a denser medium or from a medium with higher refractive index to less dense medium or a medium with lesser refractive index ( The indices of refraction have the relation n₁ > n₂, where n₁ is the refractive index of the first medium and n₂ is the refractive index of medium 2) leads to the light ray being reflected back into the first medium instead of undergoing refraction. Usually, this occurs when the incident light rays angle to the normal is greater than a certain critical angle which is the angle when the refracted ray angle in the second medium is 90°
Answer:
1373.4 N/m
Explanation:
Hooke's law states that the extension of a spring and force are related by the expression, F=kx where k is spring constant, x is extension of spring and F is the applied force. Making k the subject of the formula then
Also, F=gm hence the above formula is modified as
Taking g as 9.81 m/s2 , x as 0.5 m and m as 70 kg then
