M2 projectiles

Original post by drandy76

Ive been using Vt= 30/cos(25) and subbing the value given into the y equation to solve for t, and hence V, which i got as 15.6, i also tried using the equation of trajectory and got the same answer :s-smilie:

Would the answer happen to be something close to 22.1 ish?

Reply 4

OP

Original post by Zacken

Would the answer happen to be something close to 22.1 ish?

yeah thats the answer

Reply 5

Original post by drandy76

yeah thats the answer

Mind posting your working so I can see where you're going wrong?

Reply 6

OP

Original post by Zacken

Mind posting your working so I can see where you're going wrong?

ImageUploadedByStudent Room1456999545.651741.jpg

this is where I'm at ATM
ImageUploadedByStudent Room1456999603.654479.jpg

and this was my previous attempt

Posted from TSR Mobile

Reply 7

Original post by drandy76

this is where I'm at ATM
and this was my previous attempt

Posted from TSR Mobile

Remember that your

s=ut + \cdots

has

Unparseable latex formula:

ut = v\sin \25^{\circ} \times \frac{1}{v \cos 25^{\circ}} = \tan 25^{\circ}

, there's no

\frac{1}{v}

there since the

v

's cancel.

Reply 8

Original post by drandy76

and this was my previous attempt

Posted from TSR Mobile

This is all correct up till

\frac{1}{2}gt^2 = 10.98

then multiply both sides by 2 and divide by

g

so

t^2 \approx \frac{21.96}{9.8} \approx 2.24

whilst you've got 4 for some reason.

Reply 9

OP

Original post by Zacken

Remember that your

s=ut + \cdots

has

Unparseable latex formula:

ut = v\sin \25^{\circ} \times \frac{1}{v \cos 25^{\circ}} = \tan 25^{\circ}

, there's no

\frac{1}{v}

there since the

v

's cancel.

Thanks i finally got it :^_^:

, it started to look similar to one of (many) failed working, after looking back i didnt multiply 3 by v^2 initially :doh:

Reply 10

Original post by drandy76

Thanks i finally got it :^_^:

, it started to look similar to one of (many) failed working, after looking back i didnt multiply 3 by v^2 initially :doh:

Awesome. See my reply to why your other method with finding t didn't work either. :biggrin:

Reply 11

OP

apparently i decided it was appropriate to divide by 4.9 even after multiplying both sides by 2, Mechanics is preventing from even doing basic math :frown:

Original post by Zacken

Awesome. See my reply to why your other method with finding t didn't work either. :biggrin:

Reply 12