Projectile Motion Circular Motion Relative Motion PHYS116 A03

Projectile Motion, Circular Motion, Relative Motion PHYS-116 A-03, 1/25/11, Lecture 4 Momchil Velkovsky

Acceleration

What is the direction of the rover’s average acceleration vector for the time interval from t = 0. 0 s to t = 2. 0 s? ¡ ¡ ¡ A. up and to the left B. up and to the right C. down and to the left D. down and to the right E. none of the above

Acceleration of the rover

Our rover again vx= – (0. 5 m/s 2)t vy=(1. 0 m/s) + (0. 075 m/s 3)t 2 We can find ax and ay independently! Acceleration: ax= – 0. 5 m/s 2 ay=2*(0. 075 m/s 3)t

Motion with Constant Speed

Parallel and Perpendicular components of acceleration

The motion diagram shows an object moving along a curved path at constant speed. At which of the points does the object have zero acceleration? ¡ ¡ ¡ A. point A only B. point C only C. point E only D. points A and C only E. points A, C, and E

The velocity and acceleration of an object at a certain instant are At this instant, the object is: ¡ ¡ ¡ A. speeding up and following a curved path. B. speeding up and moving in a straight line. C. slowing down and following a curved path. D. slowing down and moving in a straight line. E. none of these is correct

A scientist aims an anesthesia dart towards a monkey. The monkey drops at the moment the scientist shoots. Will the dart hit the monkey? 1. 2. Yes No

When the dart is at point P, where will be the monkey? 1. 2. 3. A B C

A motorcycle jump y x

Watering your garden

Centripetal acceleration

An object moves at a constant speed in a clockwise direction around an oval track. The geometrical center of the track is at point O. When the object is at point P, which arrow shows the direction of the object’s acceleration vector? ¡ ¡ #1 #2 P #5 Oval track #3 #4 O ¡ A. #1 (directly away from O) B. #2 (perpendicular to the track) C. #3 (in the direction of motion) D. #4 (directly toward O) E. #5 (perpendicular to the track)

A Ferries wheel turns with 5 RPM. At points A, B and C, the acceleration is: |a. A|>|a. B|>|a. C| |a. A|<|a. B|<|a. C| |a. A|=|a. B|=|a. C| 1. 2. 3. A B C

Newton’s First Law, Inertial Reference frames

Relative motion

The monkey again y h v 0 x v 0 y l x

Next time Reading : Chapter 5 ¡ I’ll assign the next reading question and the next homework (for Monday). ¡ On Thursday I’ll give you extra practice problems. ¡