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Example: Finding the range of a projectile
For the previous example of the out of control bus which is forced to jump from a location ⟨0,40,−5⟩ with an initial velocity of ⟨80,7,−5⟩. We have now found the time of flight to be 9.59s and now want to find where the bus returns to the ground?
Facts
* Starting position of the bus ⟨0,40,−5⟩
* Initial velocity of the bus ⟨80,7,−5⟩
* The acceleration due to gravity is 9.8 ms2 and is directed downward.
* The bus experiences one force - the gravitational force (directly down).
* The bus takes 9.59s to reach the ground
Lacking
* The final position of the bus.
Approximations & Assumptions
* Assume no drag effects
* Assume ground is when position of bus is 0 in the y direction
Representations
Diagram of situation.
Diagram of forces acting on bus once it leaves the road.
Equation for calculating the final position of an object.
xf=xi+Vavg,xΔt
Solution
From the previous problem you already know the final location of the ball in the y direction to be 0 as it has met the ground after 9.59s.
Now to find the range in the x and z directions:
xf=xi+Vavg,xΔt
=0+80m/s(9.59s)
=767m
zf=zi+Vavg,zΔt
=−5+−5m/s(9.59s)
=−52.95
Final position = ⟨767,0,−52.95⟩ m