Physics-Translational Motion

what is distance?

distance is the length of the path followed by a moving object, distance is the number of steps taken

distance is a scalar quantity

what is displacement?

displacement is the position of an object compared to an origin (often a starting point), displacement is a straight line distance in steps between where you are now and some reference point (usually where you started)

displacement is the vector counterpart of distance

distance vs displacement units

distance (the length of the path) can be described with just a number of units, like 5 meters or 4 feet, whereas displacement requires a number of units and a direction, like 5 meters North or 4 feet down

displacement is never the same thing as distance, with exception

exception is displacement equal to distance for linear motion in one direction

the person’s displacement

independent of path, displacement is the straight line distance and direction from point A to point B

what is speed?

speed is distance traveled divided by time traveled, speed is a scalar

what is velocity?

velocity is displacement traveled divided by time traveled

what is average velocity?

change in velocity over change in time

what is instantaneous velocity?

change in displacement (dx) at a given instant (dt)

the magnitude of instantaneous velocity is equal to what?

speed at that instant

if the path continuously changes, what happens to the instantaneous velocity?

the direction of the velocity is continuously changing, so the instantaneous velocity is also continuously changing

what is acceleration?

acceleration is the rate of change in velocity

what happens when acceleration points in a direction that is neither parallel nor antiparallel to velocity?

it indicates a change in direction of velocity

what is translational motion?

the movement of an object along a straight line or a curved path without rotating

what does constant acceleration mean?

the direction and magnitude of acceleration must remain constant

what is rectilinear motion?

motion along a straight line

what are the uniformly rectilinear motion equations?

when appropriate, you may use delta t as an approximation for dt

what is the projectile motion diagram?

vertical acceleration is given by gravity = 9.8 m/s²

for horizontal motion, acceleration is a constant zero

for a projectile with vertical velocity (v_o) at an angle theta, the initial vertical velocity (v_o,y) is equal to v_osin(theta)

the horizontal velocity (v_x) remains v_ocos(theta)

what is peak height?

at peak height, the projectile has a vertical velocity of 0 m/s, but even at this instant, is still accelerating downwards -10 m/s²