PHYS 1111 1nd Edition Exam 1 Study Guide Lectures 1 6 Chapter 1 and 2 Scalar Quantity specified by a single number or magnitude ex Temperature speed mass Vector A quantity with both a magnitude and direction ex Force velocity displacement Kinematics motion of object without reference to cause of motion Dynamics effects that forces have on the motion of objects Statics when objects don t move Displacement x x f x i distance displacement Average Speed vs Average Velocity t t v xf v xi Acceleration t f t i Example on displacement and velocity graph Motion in free fall o Acceleration is non zero and constant o G 9 81 m s 2 or 32 2 ft s2 IMPORTANT EQUATIONS v v o at o 1 o x x o v o v t 2 1 2 o x x o v o t a t 2 o 2 2 v v o 2 a x x o Chapter 3 and 4 Can t add vectors like you add scalars have to split x and y components o X and Y are independent v v x v y a a x a y d d x d y Example h x 2 y 2 Even if velocity of particle is zero the acceleration is not necessarily zero For example if you throw a ball in the air the acceleration is always g but at the top of the trajectory the velocity is zero More practice problems 1 A car is moving with a speed of 32 m s The driver sees an accident ahead and slams on the brakes giving the car a deceleration of 3 5 m s2 How far does the car travel after the driver put on the brakes before it comes to a stop Solution v 2 v 2o 2 a x x o 2 2 0 32 2 3 5 x x 146 m 2 The slope of a line connecting two points on a position vs time graph gives a instantaneous acceleration b instantaneous velocity c average velocity d displacement e average acceleration 3 An object is thrown upwards with a speed of 13 m s How long does it take to reach a height of 4 0 m above the projection point while decending 1 2 Solution x x o v o t a t 2 1 2 4 0 13 t 9 81 t 2 t 2 3 s 4 A car starts at rest and accelerated at 6 00 m s2 How far does it travel in 3 00 s 1 2 Solution x x o v o t a t 2 2 X 6 00 3 27 0 m s 5 A rock is thrown at some angle above the horizontal with a certain velocity It reaches its highest point and starts falling down What is the velocity of the rock at the highest point of its trajectory a 0 b It is equal to its initial velocity c 9 8 m s d it is equal to its initial velocity e It is equal to its initial vertical velocity