Aballoon is at a height of 81 m and is ascending upwards with a velocity of 12m/s^2. a body of 2kg weight is dropped from it. if g=10m/s^2, the body will reach the surface of earth in how much time

Since we're observing the vertical motion of the balloon that's ascending, we can use the equation as shown below. 



where d is the height, v is the velocity, a is the acceleration, and t is the time.

Given that the balloon reached a height of 81 m at a velocity of 12 m/s². Since a body is dropped and is going downwards, acceleration is equal to g = 10 m/s². So, plugging this into the equation, we have





Seeing that we have a quadratic equation, we can apply the quadratic formula to look for its positive root (we neglect the negative root since time can not be negative). 




This means that it will take 5.4 seconds for the body to reach the ground.

5.4 seconds

The answer is

The amount used= 13.04- 1.9 = 11.14