Vectors in Physics
Scalar: Has magnitude, no direction. Ex. Distance, speed, time, temperature, charge, energy.
Vector: Mathematical quantity with magnitude and direction. Or A
Ay Ax
Kinematics – Mathematical description of motion without reference to what causes it.
Need 1. Position and 2. Time to describe it. Instantaneous Velocity = Instantaneous Velocity = magnitude of the instantaneous velocity
Acceleration: Rate of change of velocity with time Instantaneous Acceleration =
Physics 111 Summary Week 2
1D Kinematics
Relax Vector Notation: Direction given by + or –
Position: r +x or –x
Displacement:
Velocity v +v or –v
Acceleration a +a or –a
Kinematic Equations
Solving Kinematic Problems
1. Draw Diagram
2. List Givens
2. Define Coordinate System
3. Use needed equations and rearrange to solve.
2D Kinematics
-2D vectors for position and velocity. -The two components (x & y) describe motion that is independent of one another (but related by time).
Projectile Motion
-Objects that are thrown which only have the force of acceleration due to gravity act upon it.
-Usually solve for time first
Assumptions:
-negative air resistance
-acceleration due to gravity is constant downwards g=9.81m/s2
-Earth’s rotation is ignored
-Acceleration in the x-direction is 0m/s2 (Velocity in the x-direction is constant)
-Acceleration in the y-direction is 9.81m/s2
Relative Motion
Denoting Relative Velocity: Use Subscripts
Velocity of A relative to B = VAB
Rules: 1. VAB = -VBA 2. VAC = VAB + VBC
Physics Week 4 Summary
Choose a co-ordinate system parallel and perpendicular to the slope so ay = 0.
Apparent Weight
Normal Force > Weight feels heavier
Normal Force