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Answer: CALC A rocket starts from rest and moves upward
Chapter 2, Problem 51E(choose chapter or problem)
Problem 51E
CALC A rocket starts from rest and moves upward from the surface of the earth. For the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 1 2.80 m/s3)t, where the + y-direction is upward. (a) What is the height of the rocket above the surface of the earth at t = 10.0 s? (b) What is the speed of the rocket when it is 325 m above the surface of the earth?
Questions & Answers
QUESTION:
Problem 51E
CALC A rocket starts from rest and moves upward from the surface of the earth. For the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 1 2.80 m/s3)t, where the + y-direction is upward. (a) What is the height of the rocket above the surface of the earth at t = 10.0 s? (b) What is the speed of the rocket when it is 325 m above the surface of the earth?
ANSWER:
Solution 51E
Step 1
(a) The acceleration of the rocket is given by
…. (1)
Integrating equation (1) with respect to we have
… (2)
Here is the constant of integration. Now, we know that the rocket is starting from rest. Hence the initial velocity zero, so we have at , , putting the value in above equation we have
So, equation (2) becomes
… (3)
Again integrating the equation (3) with respect to we get
… (4)
Here is the constant of integration. Again we know that the rocket starts from the surface of the earth. Hence the displacement is zero at , using this value in equation (4), we can write that
Hence the displacement at any time is given by
… (4)
Now putting the value of we have
At the height of the rocket is 2133 m.