Answer: The trip takes 
Explanation:
Velocity 
is the variation of the position of a body (distance traveled 
) with time 
:
In this case, the car travels a distance 
at a velocity 
and we need to find the time it takes the trip.
Isolating :
Finally:
Answer:
a) 
, b) 
, c) 
Explanation:
a) The change in the gravitational potential energy of the marble-Earth system is:
b) The change in the elastic potential energy of the spring is equal to the change in the gravitational potential energy, then:
c) The spring constant of the gun is:
<em>Important thing is that all unitless quantity is dimensionless quantity. .</em><em>A</em><em> dimensionless physical quantity may have an unit</em>
In the outer layers of earths atmosphere gases are in ionized state primarily on account of cosmic rays . as earth rotates , strong electric current are set up due to movement of ions . these currents form earth magnetic field . and thus two equal and opposite poles of earth formed
