Projectile Motion Help (range of projectile) (1 Viewer)

[luo_ge]

Hi guys, I have an assessment next week on the projectile motion prac but I'm unsure of how to calculate the range of a projectile when given the height the projectile is launched, angle and initial velocity. Also is acceleration + or - 9.8?

Thanks in advance.

 

[pikachu975]

Acceleration can be both + or - as long as you keep it consistent with other variables, let it be positive here since there is only downward movement.

Use delta y = uyt + 1/2 ayt^2 and uy = 0 as it is at max height. Then you just sub in height of the table and calculate time of flight. After this you sub in Range = uxt, uxt is the initial velocity and time is the time of flight.

 

[Green Yoda]

In a symmetrical motion

1) Find u(x) and u(y)
2) Find the Time to Max Height by using v(y)=u(y)+0.5*a(y)*t^2 Where v(y) at max hieght = 0
3) Time to Max Height x2 = Time of Flight (as it's a symmetrical motion)
4) Use delta(x)=u(x)*t (where t is time of flight)

 

[Green Yoda]

When projectile is launched from a height

u(y)=0
find u(x)

1) Find t, by using delta(y)=u(y)+0.5*a(y)*t^2
2) Find range, delta(x)=u(x)*t