Answer: the wall contracts the force exerted by his head. The wall produces the opposite force which is equal to the force his head bangs the wall with.
Explanation: if his head exerts a much greater force than the wall can counteract the wall will be destroyed, if the wall exerts a much greater force than his head exerts he will be pushed far back and might even suffer a broken head.
The wall in this case provides the opposite reactive force.
A) 
The energy of an x-ray photon used for single dental x-rays is
The energy of a photon is related to its wavelength by the equation
where
is the Planck constant
is the speed of light
is the wavelength
Re-arranging the equation for the wavelength, we find
B) 
The energy of an x-ray photon used in microtomography is 2.5 times greater than the energy of the photon used in part A), so its energy is
And so, by using the same formula we used in part A), we can calculate the corresponding wavelength:
Answer:
1.03
Explanation:
0.02 has two significant decimal figures, so start by shortening 1.0090 to 2 decimal places (3 significant figures). Round up the decimal to become 1.1 and add .02 to get 1.3.
Gravitational potential energy is caused when an object is resting above the ground. It is released when the object is falling, not by burning substances.
Answer:
I believe the answer is D: Conductor.
