Chapter 2 Flashcards
Acceleration
Rate of change of velocity
Straight line in v-t graph
Constant acceleration
Steeper slope in v-t graph
Greater acceleration
Gradient is 0 in v-t graph
Velocity is constant
Acceleration is 0
Negative slope in v-t graph
Deceleration
Changing slope in v-t graph
Acceleration is changing
Gradient of v-t graph and
Area of v-t graph
Acceleration and
Displacement
What measures velocity and acceleration
Accelerometer
Using light gates to determine velocity and acceleration
Calculate initial and final acceleration:
u = L1/T2-T1
v= L2/ T4-T3
a = v-u/t3-t1
Using ticker-timer to determine velocity and acceleration
Dots at certain interval represent time interval
Length of interval in cm is displacement
Gradient is the acceleration
Equation 1 of equations of motion
V = u + at
Equation 2 of equations of motion
S = (u+v)/2 x t
Equation 3 of equations of motion
S = ut + 1/2at^2
Equation 4 of equations of motion
V^2 = u^2 + 2as
When the equations of motion be used
For motion in a straight line
For an object with constant acceleration
Deriving equation 1 of the equations of motion
a = v-u/t
Make v the subject
Deriving equation 2 of the equations of motion
Avg velocity = U+v/2
Displacement = avg velocity x time
S= u+v/2 x t
Deriving equation 3 of the equations of motion
Equation 1: V = u + at
Equation 2: S = u+v/2 x t
Sub v from equation 1 into equation 2
Deriving equation 4 of the equations of motion
Equation 1: v = u + at Equation 2: s = u+v/2 x t Sub t from equation 1 Find lcd and multiply Make v^2 the subject
How to find acceleration on a graph
Mark a point on the graph at time of interest
Draw a tangent to the curve at that point t
Make a right angled triangle to find gradient
How to find acceleration caused by gravity
Acceleration of free fall V = 0 Sub into s = ut + 1/2at^2 Plot on a graph Find gradient Gradient = t^2 t^2 = g/2 g= 0.84/0.20 x 2
How to find using a light gate
Find acceleration from initial and final velocity
Component vectors
Y: cos
X: sin
How to calculate the height of projectile
V^2 = U^2 + 2as Acceleration is negative U is known V is zero Find a
How to find time of a projectile
s= it + 1/2at^2 s=0 u is known G Acceleration is negative Find t
How to find the final displacement after falling a cliff
Displacement is negative
Use s = ut
The horizontal and vertical motion of a projectile and distance fallen
Horizontal: distance increase because unaffected by gravity so v = s/t
Vertical: accelerating downwards
Horizontal distance = v x t
Vertical distance: u = 0 so use s= ut
How to find the time of a projectile thrown horizontally
Find for both vertical and horizontal planes: Find horizontal and vertical velocity Find time: S = ut U= 0 Calculate t^2 Distance travelled: Distance travelled = u x t
How to find the range of a projectile
Velocity: Horizontal and Vertical components initial velocity Time: s = ut Horizontal displacement s = v x t