An aeroplane is flying horizontally at a height of 490m with a velocity of 360km/h. A bag containing ration is to be dropped to the soldiers on the ground. How far from the ground should the bag be released so that it falls directly over them.(g=9.8m/s^2)

Question

dan815 · Answer

ok lets do this

anonymous · Answer

yes

dan815 · Answer

okay so calclate the time it takes to fall first

dan815 · Answer

Vy(0)=0, 
Y(0)=450,
so
Y=1/2*at^2+450
0=1/2g*t^2+450
solve for t

dan815 · Answer

and then do 360*t, and thats how far u must drop it away

anonymous · Answer

|dw:1402480943298:dw|

dan815 · Answer

g=-'ve not positibe

anonymous · Answer

Can we use the range formula somehow
$$\huge R=u.\sqrt{\frac{ 2H }{ g }}$$

dan815 · Answer

well that is kinda wha we doing

anonymous · Answer

Ok so, let's follow the formula

dan815 · Answer

0=1/2g*t^2+450
t=sqrt(2*450/9.8)

anonymous · Answer

after multiplying by 360 i ain't gettingthe answer , i 'm getting 
3449.9
answer is 1000

dan815 · Answer

490*

dan815 · Answer

the anwer is 3600 horizontal distance away from the target

anonymous · Answer

it is given 1000

shamim · Answer

1000 m is right answer. i calculated it in my mind

anonymous · Answer

how

dan815 · Answer

no mitake

dan815 · Answer

d^y/dt^2=-9.8
dy/dt=-9.8t+k1
y=-4.9t^2+k1t+k2
y'(0)=0=k1
y(0)=490=k2
y=-4.9t^2+490
@Y being height t where height =0 
y=0=-4.9t^2+490
y=sqrt(490/4.9)
 =sqrt100 
360*sqrt100 = 3600

shamim · Answer

h=ut+(1/2)at^2
490=0*t+(1/2)*9.8t^2
490=4.9t^2
t^2=100
t=10

anonymous · Answer

.-.

shamim · Answer

the above calculation is for vertical component

shamim · Answer

now for horizontal component
s=vt

anonymous · Answer

yes

shamim · Answer

v=360km/h
convert it into m/s

shamim · Answer

t=10s

shamim · Answer

v=360*1000m/3600s

anonymous · Answer

yup got itr

anonymous · Answer

o_o you should memorise the formula

anonymous · Answer

yes i learn't projectile.......... just yesterday

shamim · Answer

anyway i slways enjoy open study

anonymous · Answer

i see

anonymous · Answer

http://www.schoolphysics.co.uk/age16-19/Mechanics/Kinematics/text/Projectiles_horizontal_projection/index.html

anonymous · Answer

http://www.schoolphysics.co.uk/age16-19/Mechanics/Kinematics/text/Projectiles_projection_at_an_angle/index.html

dan815 · Answer

omgosh xD i forgot it was in km

dan815 · Answer

sry

dan815 · Answer

360 km/h= x m/s , x=360*1000/60^2 = 100 m/s
therefore 100m/s * 10s = 1000m