Vectors, Speed, and Constant Acceleration.

Question

A rocket blasts off and moves straight upward from the launch pad with constant acceleration. After 3.0 seconds the rocket is at a height of 77 meters. (a) What are the magnitude and direction of the rocket's acceleration? (b) What is its speed at this time?

Answer 1

To solve this problem, first identify the given information, and the unknown.

Given: vi = 0      t= 3 s       d = 77 m

Unknown: acceleration = a

 

Which equation of motion connects vi, t, d, and a?  d = vit + 1/2 at^2

Substitute and solve for a.

 

 

What is the speed after 3 seconds? V = a x t

 

 

You need a book that have problems of this nature,  and strategies that can be used to solve them. I recommend "Score High in Physics" which is available on the Amazon website. It is a low cost ebook that can be readily downloaded to ipad, kindle, computer, etc.