1) a) attract
The magnetic force between two magnetic poles is attractive for two unlike poles and repulsive for two like poles. Therefore we have:
1- For two north poles, the force between them is repulsive
2- For two south poles, the force between them is repulsive
3- For a north pole and a south pole, the force between them is attractive
In this problem, we are in the situation described in 3), so the force between the poles is attractive.
2) a) motion of electrons
While electric fields are produced by static electric charges, magnetic fields are produced by charges in motion (currents). In particular, a current in a wire (where a current is simply the motion of electrons inside the wire) produces a magnetic field whose intensity is

where
I is the current in the wire
r is the radial distance from the wire
And the direction of the field lines are such that the field form concentric circles around the wire.
Step 1: Define an equation that relates the volume of a sphere to its radius.
V = 4/3*π*r3
Step 2: Take the derivative of each side with respect to time (we will define time as "t").
(d/dt)V = (d/dt)(4/3*π*r3)
dV/dt = 4πr2*dr/dt
Step 3: We are told in the problem statement that diameter is 100m, so therefore r = 50mm. We are also told the radius of the sphere is increasing at a rate of 2mm/s, so therefore dr/dt = 2mm/s. We are looking for how fast the volume of the sphere is increasing, or dV/dt.
dV/dt = 4π(50mm)2*(2mm/s)
dV/dt = 62,832 mm3/s
Answer:
Acceleration.
Explanation:
American football is one of the sports with the highest physical contact, along with boxing, mixed martial arts and rugby. Therefore, the risk of injury for players who play the sport is higher. However, many injuries in this sport have to do with blows to the head, where concussions occur that generate small neuronal short circuits due to the impact, which can cause fainting, amnesia and even vomiting.
This type of injury occurs due to the acceleration of the players when impacting their rival, which increases their strength (since it is known that the greater the acceleration the weight acquires a greater impact force).
Answer:
distance or displacement
Explanation:
the answer can be displacement or displacement. if the required measure is between two points, we can call it as distance. but if we are to find the distance moved, we call it displacement. though it sounds pretty similar, they are very different. displacement is the shortest distance of movement of a body to its final point (or to the asked point) and distance is the total distance travelled by the body. and while distance is a scalar quantity, that this value shows the magnitude, displacement is a vector quantity, that this value should show both magnitude and direction.
for example if an object travels from point A to point B that is a 10 meters away and back, the distance will be 10+10 which is 20 meters. but the displacement is 0!
since not much information is given, the answer can be both distance or displacement