The duration of time for which an object stays in air is called the hang time.
For an athlete who moves 3m horizontally during a 1.25m high jump, the hang time will be the sum of the time taken by the athlete to reach the maximum height and the time taken for the athlete to reach the ground from maximum height.
Calculate the time taken t_1 by the athlete to reach the maximum height



The athlete takes same time to reach the ground from the maximum height, so 
Calculate the hang time will be



Therefore the hang time of the athlete when he moves a horizontal distance of 3m is 1s.
Similarly, when the athlete runs 6m horizontally, then also there will not be a change in the hang time of the athlete as the hang time is independent of the horizontal distance covered.
Answer: 4.27 *10^6 N/C
Explanation: In order to calculate the electric field along the axis of charged ring we have to use the following expression:
E=k*x/(a^2+x^2)^3/2 where a is the ring radius and x the distance to the point measured from the center of the ring.
Replacing the data we have:
E= (9* 10^9* 0.3* 50 * 10^-6)/(0.1^2+0.3^2)^3/2
then
E=4.27 * 10^6 N/C
Explanation:
Formula for maximum efficiency of a Carnot refrigerator is as follows.
..... (1)
And, formula for maximum efficiency of Carnot refrigerator is as follows.
...... (2)
Now, equating both equations (1) and (2) as follows.
=

= 
= 
= 2.5
Thus, we can conclude that the ratio of heat extracted by the refrigerator ("cooling load") to the heat delivered to the engine ("heating load") is 2.5.