Answer:
A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibrations to work on it.
Answer:
C) at right angles to the direction of the motion
Explanation:
The magnetic force exerted on a charged moving particle is given by

where
q is the charge of the particle
v is the velocity of the particle
B is the magnetic field intensity
is the angle between the direction of v and B
Moreover, the direction of the force is perpendicular to both v and B. In particular, the direction can be found by using the right hand rule:
- index finger: direction of the velocity
- middle finger: direction of the magnetic field
- thumb: direction of the force (if the charge is positive, otherwise the direction must be reversed if the charge is negative)
To develop the problem it is necessary to apply two concepts, the first is related to the calculation of average data and the second is the Boltzmann distribution.
Boltzmann distribution is a probability distribution or probability measure that gives the probability that a system will be in a certain state as a function of that state's energy and the temperature of the system. It is given by

Where,
energy of that state
k = Boltzmann's constant
T = Temperature
With our values we have that
T= 250K




To make the calculations easier we can assume that the temperature and Boltzmann constant can be summarized as



Therefore the average energy would be,

Replacing with our values we have


Therefore the average internal energy is 
Answer:
Torque = –207.4 Nm
Explanation:
Given M = 3.2kg, r = 5.4m, α = –12rad/s² (it is slowing down)
Torque = I × α
α = angular acceleration
I = moment of inertia
I = MR² for a circular hoop
Torque = 3.2×5.4×(– 12)
Torque = –207.4 Nm