Let's use the mirror equation to solve the problem:
where f is the focal length of the mirror,
the distance of the object from the mirror, and
the distance of the image from the mirror.
For a concave mirror, for the sign convention f is considered to be positive. So we can solve the equation for
by using the numbers given in the text of the problem:
Where the negative sign means that the image is virtual, so it is located behind the mirror, at 8.6 cm from the center of the mirror.
W = Fd = 4(2100) = 8400 J
So the answer is A) 8400 J
I was just rewriting my notes on the work lesson I did in class today, so I saw this question at the perfect time!! :)
Hope it helps!! :)
Answer:
Explanation:
Using the first law of thermodynamics:
Where 
is the change in the internal energy of the system, in this case 
, 
is the heat tranferred, and 
is the work, 
with a negative sign since the work is done by the system.
From the previous equation we solve for heat, because it is the unknown variable in this problem
And replacing the known values:
The negative sign shows us that the heat is tranferred from the system into the surroundings.
Answer:
Explanation:
A pressure that causes the Hg column to rise 1 millimeter is called a torr. The term 1 mmHg used can replaced by the torr.
1 atm = 760 torr = 14.7 psi.
A.
120 mmHg
Psi:
760 mmHg = 14.7 psi
120 mmHg = 14.7/760 * 120
= 2.32 psi
Pa:
1mmHg = 133.322 Pa
120 mmHg = 120 * 133.322
= 15998.4 Pa
B.
80 mmHg
Psi:
760 mmHg = 14.7 psi
80 mmHg = 14.7/760 * 80
= 1.55 psi
Pa:
1mmHg = 133.322 Pa
80 mmHg = 80 * 133.322
= 10665.6 Pa
I think frequency it sounds like the correct answer but I am not completely sure if I am correct
