Y2, C6 - Projectiles Flashcards
What is the vertical acceleration with projectile motion
g
What is the horizontal acceleration with projectile motion
0
What does projectile motion being a parabola mean
They are symmetrical
What can you consider separately with projectile motion
Vertical and horizontal components
What value in suvat bridges vertical and horizontal motion
t - time
Time of the journey
How do you find the distance travelled in projectile motion
Pythagoras of the horizontal and vertical distances
What is an angle of:
a) elevation
b) depression
a) Angle upwards
b) Angle downwards
What is the vertical velocity at the highest point of a projectile motion
0
A particle is projected with speed 28m/s with angle of elevation 30 degrees, what are the horizontal and vertical components of velocity
Horizontal = 28 cos30
Vertical = 28 sin30
If you take vertical motion downwards to be +ve, will your greatest height be +ve or -ve
-ve
How do you find the time of a projectile motion journey
Set distance (s) to be 0 if projected from flat or the -ve of the elevation and solve suvat
How do you find the length of time a particle is above a set distance
Set distance (s) to be the value
Solve simultaneously with suvat
Take the smallest t away from the biggest t to find answer
How do you find the value for U (initial speed) when not given it
suvat for horizontal and vertical components, as t is equal you can solve for U as a numerical value
Does horizontal speed change in projectile motion
NO
What do tangents to the projectile motion tell you
The direction the particle is moving in
A particle is projected from an elevated point A to a point B. How would you find the time after projection when the particle is moving parallel to AB
The tangent to the parabola would create a triangle
The triangle should be similar to the triangle OAB
Find gradient of triangle OAB
You know that the tangent triangle has a constant horizontal component so plug in the gradient and work out the vertical component from the gradient and horizontal component
Plug vertical velocity component into suvat to find time
What is the range of a projectile motion
The horizontal distance it travels
A particle is projected with angle x and velocity U, how would you find the range, R, on the horizontal plane
suvat the horizontal motion
u = Ucosx
a = 0
u = s/t –> s = ut
t = (2U * sinx) / g (derived from using vertical motion to find T)
rearrange suvat equations
R = (U^2 / g) * sin2x
What equation for speed can you use with horizontal motion
speed = distance / time
A particle is projected with angle x and velocity U, how would you find the time of the flight, T
suvat the vertical motion
u = Usinx
a = -g
s = 0
t = T
rearrange suvat and select the value of T where T doesn’t equal 0
T = (2U * sinx) / g
For a particle with initial velocity U and at angle α above horizontal and moving freely under gravity:
What is the general result for time of flight
Time of flight = (2U sinα) / g
For a particle with initial velocity U and at angle α above horizontal and moving freely under gravity:
What is the general result for time to reach greatest height
Time to reach greatest height = (U sinα) / g
For a particle with initial velocity U and at angle α above horizontal and moving freely under gravity:
What is the general result for range on horizontal plane
Range on the horizontal plane = (U^2 sin2α) / g
For a particle with initial velocity U and at angle α above horizontal and moving freely under gravity:
What is the general result for equation of trajectory
Equation of trajectory = x tanα - ((gx^2) / (2U^2)) * (1 + tan^2 α)
