Answer:
Mental time travel has been studied by psychologists, cognitive neuroscientists, philosophers and in a variety of other academic disciplines. Major areas of interest include the nature of the relationship between memory and foresight, the evolution of the ability (including whether it is uniquely human or shared with other animals), its development in young children, its underlying brain mechanisms, as well as its potential links to consciousness, the self, and free will.
Explanation:
Explanation:
Given that,
The mean kinetic energy of the emitted electron, 
(a) The relation between the kinetic energy and the De Broglie wavelength is given by :



(b) According to Bragg's law,

n = 1
For nickel, 



As the angle made is very small, so such an electron is not useful in a Davisson-Germer type scattering experiment.
Answer:
The acceleration is 
Explanation:
From the question we are told that
The lift up speed is 
The distance covered for the take off run is 
Generally from kinematic equation we have that

Here u is the initial speed of the aircraft with value 0 m/ s give that the aircraft started from rest
So

=> 
Answer:
True The net force must be zero for the acceleration to be zero
Explanation:
In order to analyze the statements of this problem we propose your solution.
First let's look at Newton's first, which stable that every object is at rest or with constant speed unless something takes it out of this state (acceleration)
Now let's look at the second postulate, which says that force is related to the product of the mass of a body and its acceleration.
As a result of these two laws, for a body is a constant velocity the summation force on it must be zero.
Now we can analyze the statements given.
True The net force must be zero for the acceleration to be zero
False. If the force is different from zero, there is acceleration that changes the speeds
False. There may be forces, but the sum of them must be zero
False. If a force acts, the acceleration is different from zero and the speed changes
<span>The intermolecular attractions are the caause of attraction between the molecules of liquid water. These intermolecular bonding interactions in water is due to Hydrogen bonding. The hydrogen bonding is in between O and H atoms.</span>