A-Level Maths: Q5-11 Projectiles: From the Ground Example 5 Integration Method

[a.]

Hi Jack. What would be your prefered method for tackling these questions, SUVAT or Integration? Efficiency and accuracy would obviously be key in exam questions. Thanks

[masonbluewood]

Hi Tlmaths, your videos are very helpful. Thanks for making them.

I have a question regarding your integration method.

In class I was given this question,
A particle is projected with speed of 21m/s at angle of elevation of theta. Given the greatest height reached above the Pt of projection is 15m, find theta.

I used your integration method on all previous questions, getting them correct. However I couldn’t do this question.

I ended up using the vertical displacement I got from integration, then setting that = 15 and substituting t into it from finding when vertical velocity is = 0 ( as that is when projectile is at its greatest height). I ended up getting some complicated equation that would take ages to solve for sin(ø).

I asked the teacher, who suggests using SUVAT and he simply said to use equation v2 = u2 -2as
That got the answer straight away.

So how would you do that question with the integration method quickly, as you know we don’t have all day in the exam.

Thanks, Mason.