Could you show me how to set up the problem? A 1.14x10^4-kg lunar landingcraft i
ID: 1764918 • Letter: C
Question
Could you show me how to set up the problem?A 1.14x10^4-kg lunar landingcraft is about to touch down on the surface of the moon, where theacceleration due to gravity is 1.6 m/s2. At an altitudeof 165 m the craft's downwardvelocity is 18.0 m/s. To slow down thecraft, a retrorocket is firing to provide an upward thrust.Assuming the descent is vertical, find the magnitude of the thrustneeded to reduce the velocity to zero at the instant when the crafttouches the lunar surface.
Could you show me how to set up the problem?
A 1.14x10^4-kg lunar landingcraft is about to touch down on the surface of the moon, where theacceleration due to gravity is 1.6 m/s2. At an altitudeof 165 m the craft's downwardvelocity is 18.0 m/s. To slow down thecraft, a retrorocket is firing to provide an upward thrust.Assuming the descent is vertical, find the magnitude of the thrustneeded to reduce the velocity to zero at the instant when the crafttouches the lunar surface.
Explanation / Answer
A 1.14x10^4-kg lunar landingcraft is about to touch down on the surface of the moon, where theacceleration due to gravity is 1.6 m/s2. At an altitudeof 165 m the craft's downwardvelocity is 18.0 m/s. To slow down thecraft, a retrorocket is firing to provide an upward thrust.Assuming the descent is vertical, find the magnitude of the thrustneeded to reduce the velocity to zero at the instant when the crafttouches the lunar surface.final velocity=0m/sec
initial velocity at a height of 165m=18m/sec
h=165m
acceleration due to gravity on moon =1.6m/sec2
let the upward thrust=F
due to the thrust the acceleration developed in the oppositedirection=F/1.14x10^4
hence the resultant acceleration=[(F/1.14x10^4)-1.65]
now using the relation
v*v=u*u+2as
0=18*18+2[(F/1.14x10^4)-1.65]*165
calculating we get thrust =F=30002.72N