I agree with the other comment
If "0.3 minute" is correct, then it's 9,543,272 Joules.
If it's supposed to say "0.3 SECOND", then the KE is 2,651 Joules.
Forces are balanced when net force on the object is zero or the sum of all force on the object is zero.
For book kept on a shelf, the weight of the book in down direction is balanced by the normal force on the book by the shelf. hence the book kept on a shelf is an example of balanced force.
In case of air rushing out of balloon , the balloon experience a net force by the air coming out of it.
rolling over and falling off the bed , the object falls under gravity force.
a car speeding up accelerates. since it accelerates , it has net force on it.
In fresh water sound waves travel at 1497m/s at 25 degrees, I'll assume that's the characteristics of the water.
If it's 0.01s then you need to divide the speed by 100 to get the, 14.97, however it gets there and back in that time so you need to halve it.
<u>7.485m</u>