Answer:
See the explanation.
Explanation:
The speeds of sound depend upon the temperature of the medium. As the temperature increased in the afternoon, the speed of sound increases. Then the time taken by reflected sound will be less than 0.1 sec in the afternoon. And to hear an echo the time gap between an original sound and reflected sound must be at least 0.1 sec. That is why the student could not hear the echo at all in the afternoon.
Answer:
Explanation:
Given that,
The work function for silver is 4.73 eV.
We need to find the value of the work function from electron volts to joules.
We know that,
For 4.73 eV,
So, the work function for silver is 
.
(And don't forget that an object going around a curve at a constant speed is also accelerating.)
I believe there are two reasons:
1). The term is inadequately taught in the American public school system ... along with much of the rest of Science and Math in general.
2). The word became permanently and indelibly corrupted when the automotive industry decided to name the gas pedal the "accelerator".
One of the many random useless factoids that I carry around
in my head is the factoid that 60 miles per hour is equivalent
to exactly 88 feet per second.
So in three seconds at that speed, you would cover exactly
(3 x 88) = 264 feet.
7. First write down all the known variables while separating the values for each direction:
x-direction:
vix = 20m/s
vfx = 20m/s
x = 39.2m
y-direction:
viy = 0m/s
ay = -9.8m/s^2
y = ?
Based on the knowns, the first step is to calculate the time of flight from the x-direction as it will be the same as value for the y-direction. Find the correct kinematic equation to do so:
x = (1/2)(vix+vfx)t
(39.2) = (1/2)(20+20)t
1.96s = t
Now that we have the time of flight, we can use the kinematic equation that will relate the known variables in the y-direction:
y = viy*t + (1/2)ay*t^2
y = (0)(1.96) + (1/2)(-9.8)(1.96)^2
y = -18.82m (Value is negative because gravity constant was negative. It is the height reference that from the top of the building down, which is why it is negative. The sign can be ignored for this question.)
8. First write down all the known variables while separating the values for each direction:
x-direction:
x = 12m
vfx = 0m/s
vix = ?
y-direction:
y1 = 1.2m
y2 = 0.6m
viy = 0m/s;
ay = -9.8m/s^2
First find time in the y-direction as it would be the same value for the x-direction.
(y2 - y1) = viy*t + (1/2)ay*t^2
(-0.6) = (0)t + (1/2)(-9.8)t^2
t = 0.35s
Now that we have the time of flight, we can use the kinematic equation that will relate the known variables in the x-direction:
x = (1/2)(vix+vfx)t
(12) = (1/2)(vix+(0))(0.35)
68.6m/s = vix
