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:

The direction in which the magnetic force is acting on the charge is upwards.
<h3>What is Magnetic force?</h3>
This is the attraction and repulsion which usually occurs during the motion of electrically charged particles.
In the magnetic field, the charge is moving to the left. Therefore the direction the magnetic force is acting on the charge is upwards which is gotten via right hand rule.
Read more about Magnetic force here brainly.com/question/25932320
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Density = mass/volume
= 4300/10000
= 0.43 g/mL.
Therefore density of liquid propane is 0.43 g/mL.
Hope this helps!
The scientist is likely to be studying kinematics.
Kinematics is the branch of science, specifically physics, which is concerned with the motion of objects without reference to the forces that induce this motion. An example of kinematics is studying the change in velocity of an object over time or the distance covered by an object in a specified amount of time.
The acceleration is 
Explanation:
We can solve the problem by applying Newton's second law of motion: in fact, the net force acting on an object is equal to the product between the mass of the object and its acceleration. Therefore we can write:

where:
is the resultant force acting on the object
m is its mass
a is its acceleration
In this problem, we have the following forces acting on the system:
(forward)
(backward)
So, Newton's second law can be rewritten as:

where:
m = 1050 kg is the mass of all the students
Solving the formula for a, we find the acceleration of the system:

Learn more about Newton's second law:
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