Robert has just bought a new model rocket, and is trying to measure its flight c
ID: 1551920 • Letter: R
Question
Robert has just bought a new model rocket, and is trying to measure its flight characteristics. The rocket engine package claims that it will maintain a constant thrust of 11.7 N until the engine is used up. Robert launches the rocket on a windless day, so that it travels straight up, and uses his laser range-finder to measure that the height of the rocket when the engine cuts off is 16.8 m. He also measures the rocket's peak height, which is 21.3 m. If the rocket has a mass of 0.713 kg, how much work is done by the drag force on the rocket during its ascent?Explanation / Answer
Work done by thrust
Wt=F*dY=11.7*16.8=196.56 N
work done by gravity
Wg=-mgh=-0.713*9.81*21.3=-148.98 N
work done by drag force
Wdrag=-(196.56-148.98)=-47.58 J