projectile question (2 Viewers)

[user18181818]

can someone explain how to do (i) please

 

[Unovan]

Derive the vertical component and let it equal to 0 to find t when the vertical component = 3h

Then sub that t value into the vertical component and you should be able to solve for vsin(a)

 

[user18181818]

ah got it thanks!

 

[user18181818]

how do u do (iv)?

 

[scacredcat]

where is this question from? also are there solutions to it anywhere

 

[user18181818]

where is this question from? also are there solutions to it anywhere

North Sydney Boys
That's the solutions I have no idea what they're doing

 

[scacredcat]

oh my lord im so going to fail this

 

[user18181818]

don't worry so am i

 

[scacredcat]

the mystery mark is calling my name

also for (iv) I think they're using the fact that at Q, the plane/projectile will be at point h because of the symmetry, so it uses that to find the
1 = 12x/d (1 - x/d), then they multiply through by d^2 just for laughs to make it a bit neater then solve for x to find horizontal range at point h (using quadratic formula), then just simplify for a bit. I think then, because v = x/t and v = 100(3 + root6) they set them equal then multiply the 100(3 + root6) by t, cancel out the (3 + root6) and finish it off? idk if that makes sense or not but that what i got from it

 

[SB257426]

North Sydney Boys
That's the solutions I have no idea what they're doing
View attachment 40300

In iv) they are equating the height of the plane with the height of the rocket. They do this by letting h = cartesian equation of rocket

then they solve for x because they obtained a quadratic in terms of d and look for the larger solution because we know it strikes at q

We know that for the rocket: Range = 100(3+sqrt6)t

now we know what x is from solving the quadratic... we can sub it into the equation: x = 100(3+sqrt6)t, and solve for t

 

[SB257426]

oh my lord im so going to fail this

don't worry so am i

North Sydney boys papers are meant to be difficult lol.. its just really good for practice.

 

[Luukas.2]

This question is a modified form of a question from the old Fitzpatrick book, which also shows up (with a different variation) in Cambridge... and the original Fitzpatrick question had no structure provided to guide you.