Projectile Motion Q - Will this ever be in the HSC? (1 Viewer)

[espiritulol]

This is from a half-yearly exam 2001 Terra Sancta College. Since the syllabus got amended in 2002 (I think), would this be a question to pop up in the actual HSC? I just haven't seen anything like it in recent HSC past papers.

Regardless, can someone please do it for me

Thanks!

 

[pdang]

Well if we account for the varying mass of the rocket, we use the equation m.dv = -v_g.dm
where m is the mass of the rocket (variable) and v_g is the velocity of the gases (500) and v is the velocity of the rocket (variable)
dividing by m and integrating you get v_f - v_i = v.ln(m_f/m_i)
throw in your numbers and you can find v_f.

Otherwise if we assume constant mass then you can just use the equation T = v_g dm/dt
where dm/dt is the rate of gas emission (100)
Equate this to F = ma, change a to (v_f - v_i)/t and solve for v_f

 

[pdang]

Although I don't remember this being in the syllabus

 

[espiritulol]

Thanks so much!

 

[someth1ng]

I think they can but it is very difficult and so, it is unlikely that they will.