# Homework Help: 2 linear motion problems

1. Sep 2, 2008

### thermisius

hi i have 2 questions on linear motion that i could use some help on step by step.

1. Jules Verne in 1865 proposed sending men to the moon by firing a space capsule from a 220-m cannon with final velocity of 10.97 km/sec.. What would have been the unrealistically large acceleration experienced by the space travelers during launch? Compare your answer with the free-fall acceleration,9.8 m/sec.

2. A model rocket is launched straight upward with an initial speed of 50.0 m/sec.. It accelerates with a constant upward acceleration of 2.00m/sec2 until its engines stop at an altitude of 150 m. (a) what is the maximum height reached by the rocket? (b) how long after lift off does the rocket reach its maximum height? (c) How long is the rocket in the air?

2. Sep 2, 2008

### Defennder

1. Use the definition of acceleration here. Assume average acceleration.

2. You need to use the 3 famous kinematics equations here. As for (c), the amount of time it is in the air is the total time taken to go up and for it to come crashing down.