in this video i'll talk about how much force or the thrust is required to propel a rocket upward so we have we are given a rocket here the mass of the rocket is given which is 15 000 kilogram that's the mass of the rocket and we are propelling the rocket with an acceleration which is 2.5 meter per second square and now we need to find out what is the force how much force is required so in this case the weight if we just look at the free body diagram the weight is the downward and the force the propelling force or what you call the thrust is upward that the force is taking the rocket upward the acceleration is given as well so how we're going to solve this problem we simply can write down f thrust is equal to mg so we can write down f equals to mg see when the system is either at rest or the system it is moving with a constant velocity but in this particular problem the rocket is accelerating so we going to use the newton's second law of motion to write down the equation of motion so we know that the newton's second law of motion is f is equal to m a here f this is the net force or the sum of all the forces in one direction this force is equal to m a and what is the net force now so as the system is moving up the net force is f thrust this force minus mg that's the net force because these two forces are acting opposite this is in positive y-axis and this is a negative y-axis so these two forces are opposite so f thrust minus mg and if i solve for f thrust then i what i get is f thrust is equal to m g plus a the g is acceleration due to gravity which is nine point eight and a is given which is two and a half and the mass is given fifteen thousand kilogram and if you solve that's the thrust we need to apply okay so this is the force required i will call the thrust force or the force to propel rocket upward with this acceleration that's it again if you have any questions write down your questions in the comment section below and at the end do not forget to like share and subscribe the channel thank you very