Answer:
D. The cart is moving at a constant speed or velocity
Explanation:
Equilibrium is a state of body in which it is either at rest or moves with uniform velocity. The sum of forces acting on such a body is always zero and the sum of all the torques acting on it is also zero.
There are two types of equilibrium as follows:
Static Equilibrium: When a body is at rest it is said to be in static equilibrium.
Dynamic Equilibrium: When a body is moving with constant velocity, then it is said to be in dynamic equilibrium.
Hence, the correct option here will be:
<u>D. The cart is moving at a constant speed or velocity</u>
Explanation:
It is given that,
Mass of lithium, 
It is accelerated through a potential difference, V = 224 V
Uniform magnetic field, B = 0.724 T
Applying the conservation of energy as :


q is the charge on an electron

v = 78608.58 m/s

To find the radius of the ion's path in the magnetic field. The centripetal force is balanced by the magnetic force as :



r = 0.0078 meters
So, the radius of the path of the ion is 0.0078 meters. Hence, this is the required solution.
Answer:
i)20369 photons
ii) 40 ps
Explanation:
Momentum of one Sodium atom:

In other to stop it, it must absorb the same momentum in photons:

Now, for the minimun time, we use the speed of light and the wavelength. For the n photons:
