Answer:
Explanation:
Convert the mass to kg:
375g = 375/1000kg = 0.375kg
F = ma
-20 = 0.375a
a = -20/0.375
a = -53
The object is accelerating at 53m/s/s backwards assuming that the forward motion is positive.
A) d. 10T
When a charged particle moves at right angle to a uniform magnetic field, it experiences a force whose magnitude os given by

where q is the charge of the particle, v is the velocity, B is the strength of the magnetic field.
This force acts as a centripetal force, keeping the particle in a circular motion - so we can write

which can be rewritten as

The velocity can be rewritten as the ratio between the lenght of the circumference and the period of revolution (T):

So, we get:

We see that this the period of revolution is directly proportional to the mass of the particle: therefore, if the second particle is 10 times as massive, then its period will be 10 times longer.
B) 
The frequency of revolution of a particle in uniform circular motion is

where
f is the frequency
T is the period
We see that the frequency is inversely proportional to the period. Therefore, if the period of the more massive particle is 10 times that of the smaller particle:
T' = 10 T
Then its frequency of revolution will be:

Answer:
The cornea of an eye is avascular
Explanation:
The healing process in case of a cornea transplant is slow, because the cornea is of an eye is avascular, i.e., it does not contain blood vessels and in the absence of the blood vessels in the cornea tissue the nutrients and oxygen is not able to get delivered there.
Thus the immune system, without the blood vessels in the cornea is weak and hence healing takes time in case of cornea transplant.
Work is done. work=forcexdisplacement. the ice skater glides 2 meters (displacement), so yes.