Projectiles Flashcards
what would be the vertical acceleration downwards of a ball if it was dropped from rest
9.8ms-2
what would be the vertical acceleration of a ball if it was thrown horizontally
9.8ms-2
out of the two balls, which one would hit the ground first and why
- they would both hit the ground at the same time
- as both of their vertical accelerations downwards are the same and constant
what is causing the balls to accelerate downwards at the same acceleration
gravity
if the vertical acceleration of the ball thrown horizontally was equal to the ball which was simply dropped, what does that imply about the relationship between horizontal and vertical motion
the horizontal motion had no impact on the vertical motion downwards
how would you calculate the horizontal motion of the projectile
- by considering the horizontal and vertical planes separately
- in the vertical plane the ball will accelerate downwards at 9.8ms-2
- whereas in the horizontal plane the velocity remains constant
what would you be using the equations of motion for when applied to the vertical motion and why
- you would be using an equation to calculate the length of time the projectile was in the air
- so that you can calculate the horizontal distance travelled
how would you use the calculated time to calculate the horizontal distance travelled
- the velocity of the projectile horizontally will be constant
- assuming an absence of air resistance
- which means that it can be regarded as the average velocity
- and with time you can calculate the displacement with v = s/ t just like you would with a car eg
a gun is positioned in a circuit so that it is pointing at a can held up by an electromagnet. when the bullet is shot, the circuit will be broken which means that the can will begin falling. would the bullet always hit the can (despite its speed, it should be enough to cover the distance between it and the can before they hit the floor)) and why
- yes
- because when the bullet is shot it will begin travelling horizontally at a constant velocity (if no air resistance)
- when it is released and the can is released simultaneously they will both begin accelerating downwards due to gravity
- this is the same for both objects (9.8ms-2) so their horizontal planes relative to each other while falling will be aligned
- so as the bullet travels closer to the can, it will hit no matter how fast or slow it is
if an object was thrown at an angle, what would need to be drawn to able to calculate the vertical and horizontal velocities
a right angled triangle
what would the right angled triangle look like
- the initial velocity would be the hypotenuse
- which is drawn from the beginning of the path of the projectile
- the horizontal velocity would be the base of the triangle
- completing the angle and acting as the adjacent
- while the vertical velocity would make the opposite side pointing upwards
where would the vertical velocity actually be if a triangle had to be made and does it matter
- it would be at the beginning bottom part of the initial velocity line which wouldnt make a triangle
- but it wouldnt matter as the magnitude would still be the same on either side
- its just that a triangle needs to be made for some pythag
if the initial velocity was the hypotenuse and the angle was made at the bottom left of the triangle, what would be the trig values for the horizontal velocity (u)
- the hypotenuse is h
- the horizontal is a
- the vertical is o
- tying to find a, it would be cos theta = (a / h)
- so a = h cos theta
- also written as u cos theta
if the initial velocity was the hypotenuse and the angle was made at the bottom left of the triangle, what would be the trig values for the vertical velocity
- the hypotenuse is h
- the vertical is o
- the horizontal is a
- trying to find o, so sin theta = o / h
- so o = h sin theta
- also written as u sin theta
