Finding max height and speed before it hits the ground of a rocket

by llach
Tags: ground, height, hits, rocket, speed
llach is offline
Feb10-10, 06:18 AM
P: 4
1. The problem statement, all variables and given/known data

A model rocket initially at rest on the ground is fired vertically upward, and the engine thrust produces a constant acceleration a = 40 m/s2. After running for 2.5 s the engine is cut off and then the rocket is in free fall. (a) Find the maximum height that the rocket reaches. (b) Find the speed of the rocket just before it hits the ground.
Ans: (b) 635 m (c) 112 m/s
Note: The rocket travels with 40 m/s2 acceleration during the first 2.5 s (gravity effect included).

2. Relevant equations

3. The attempt at a solution
Phys.Org News Partner Science news on
NASA's space station Robonaut finally getting legs
Free the seed: OSSI nurtures growing plants without patent barriers
Going nuts? Turkey looks to pistachios to heat new eco-city
rl.bhat is offline
Feb10-10, 09:10 AM
HW Helper
P: 4,442
In the relevant equations, can you write the kinematic equations. And using the given data, you can select a proper equation to solve the problem.

Register to reply

Related Discussions
Calculating Speed of Falling Banana - "Just Before" it Hits Ground? Introductory Physics Homework 2
What hits the ground first?? Introductory Physics Homework 4
Rocket Lab, Finding Initial Velocity, Height Given time. Introductory Physics Homework 9
Finding height of a well using speed of sound Introductory Physics Homework 3
Finding Range, Max Height and Speed of Projectile Introductory Physics Homework 4