1. Instructor: Dr. Tatiana Erukhimova
Physics 218: Mechanics
Instructor: Dr. Tatiana Erukhimova
Lecture 10

4. A faulty model rocket moves in the xy-plane (the positive y-direction is vertically upward). The rocket’s acceleration has components ax(t)=t2 and ay(t)=-t, where =2.50 m/s4, =9.00 m/s2, and =1.40 m/s3. At t=0 the rocket is at the origin and has velocity with and
Calculate the velocity and position vectors as functions of time.
What is the maximum height reached by the rocket?
What is the horizontal displacement of the rocket when it returns to y=0?

5. A physics professor did daredevil stunts in his spare time
A physics professor did daredevil stunts in his spare time. His last stunt was an attempt to jump across a river on a motorcycle. The takeoff ramp was inclined at 53.00, the river was 40.0 m wide, and the far bank was 15.0 m lower than the top of the ramp. The river itself was 100 m below the ramp. You can ignore air resistance. a) What should his speed have been at the top of the ramp to have just made it to the edge of the far bank? b) If his speed was only half the value found in (a), where did he land?

6. First exam Tuesday, September 17, 7 – 8 pm
Sections 549, HELD
Sections 551, HELD
Sections 570, HELD

7. No calculators and cell phones
BRING YOUR STUDENT ID!
No calculators and cell phones
All liquids, gels and aerosols must be in three-ounce or smaller containers.

8. What is included?
Chapters 1-4
Kinematics, vectors

11. Kinematics

12. In components:

13. If is given, you can find and

14. Vectors

15. Friendly advice
DO NOT…

16. DO NOT use Const acceleration case formulas when acceleration is a function of time. You have to integrate or differentiate! What are the Const acceleration case formulas?

17. DO NOT write the vector sign over a projection!

18. Do Not Forget to
Write down what is given and express the answer in terms of what is given
Box the answer
Indicate the origin and positive x and y

19. Have a great day!
Reading: Chapter 5