1. Physics 218: Mechanics Instructor: Dr. Tatiana Erukhimova Lecture 9

2. A cannon at the origin points up at an angle θ with the x axis. A shell is fired which leaves the barrel with a velocity of magnitude V m. a)When does the shell reach its maximum height? b)What is the maximum height? c)What is the range (horizontal distance)? d)What is the velocity of the shell when it hits the ground?

3. 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 53.0 0, 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?

4. A can drops from a magnet just when a bullet is shot from a gun: Find the angle that the gun must be aimed at to hit the can.

5. A faulty model rocket moves in the xy-plane (the positive y- direction is vertically upward). The rocket’s acceleration has components a x (t)=  t 2 and a y (t)=  -  t, where  =2.50 m/s 4,  =9.00 m/s 2, and  =1.40 m/s 3. At t=0 the rocket is at the origin and has velocity with and a)Calculate the velocity and position vectors as functions of time. b)What is the maximum height reached by the rocket? c) What is the horizontal displacement of the rocket when it returns to y=0?

6. Have a great day! Reading: Chapters 4, 5