Answer:
The velocity is 31.25 m/s and direction is toward west.
Explanation:
Given that,
Distance 
Magnetic field 
Mass of proton 
Radius of earth 
Radius of orbit 


We need to calculate the speed
Using formula of magnetic field


Put the value into the formula


Hence, The velocity is 31.25 m/s and direction is toward west.
As we know that two charges exert force on each other when they are placed near to each other
The force between two charges is given as

here we know that
= two different point charges
r = distance between two point charges
also we know that two similar charges always repel each other while two opposite charges always attract each other
so here correct answer would be
<em>A. A positive and negative charge attract each other.</em>
Answer:
Due to inertia of restttttttrestrestrestrest
Answer:
Concrete
Explanation:
The speed at which sound propagates is medium dependent. As one of the forms of mechanical waves, sound requires a material medium for propagation from place to place.
- Sound travels with the least speed in air because air particles are far apart and they are randomized.
- Sound travels with the greatest speed in solids. Concrete is the only solid material given in the choice.
The speed of sound increases from air to liquid and to solid.
Speed is defined as the distance over time. So in measuring the speed of a car, the most manual thing that we can do besides using a speedometer is to measure a certain distance then measure the time at which the car passes that distance then divide the distance over the time. Then determine the speed limit.