I'm guessing that this is a problem to find the weight of a 90kg mass on a planet where the acceleration of gravity is 4 m/s^2. (Much less gravity than Earth, a little more than Mars.)
Just do the multiplication, and you get
360 Newtons.
Answer:
The correct answer is the third option: The kinetic energy of the water molecules decreases.
Explanation:
Temperature is, in depth, a statistical value; kind of an average of the particles movement in any physical system (such as a glass filled with water). Kinetic energy, for sure, is the energy resulting from movement (technically depending on mass and velocity of a system; in other words, the faster something moves, the greater its kinetic energy.
Since temperature is related to the total average random movement in a system, and so is the kinetic energy (related to movement through velocity), as the thermometer measures <u>less temperature</u>, that would mean that the particles (in this case: water particles) are <u>moving slowly</u>, so that: the slower something moves, the lower its kinetic energy.
<u>In summary:</u> temperature tells about how fast are moving and colliding the particles within a system, and since it is <em>directly proportional</em> to the amount of movement, it can be related (also <em>directly proportional</em>) to the kinectic energy.
The electric field is always perpendicular to the surface outside of a conductor. TRUE
<span> If an electron were placed on an electric field line, it would move in a direction perpendicular to the field. FALSE, it would move in an anti-parallel direction because its charge is negative </span>
<span>Electric field lines originate on positive charge and terminate on negative charge. TRUE ; but they can also go to infinity </span>
It is possible for two electric field lines to cross each other.
<span> Usually FALSE; though technically possible at special points where field is zero. </span>
If an electron and a positron were in the presence of a very strong electric field, they would move away from each other.
<span> TRUE; one is positive, and one is negative. If the field is strong enough, the action of the field will overcome the mutual attraction between them </span>
It is not possible for the electric field to ever be zero. FALSE: it IS possible, inside a conductor for instance
If a proton were placed on an electric field line, it would move in a direction anti-parallel to the field.
<span> FALSE: being positive, it would move in the SAME direction as the field</span>ic
Answer:
(a) A = m/s^3, B = m/s.
(b) dx/dt = m/s.
Explanation:
(a)

Therefore, the dimension of A is m/s^3, and of B is m/s in order to satisfy the above equation.
(b) 
This makes sense, because the position function has a unit of 'm'. The derivative of the position function is velocity, and its unit is m/s.