A rescue plane is flying at constant elevation of 1200m with a speed of 430km\hr towards a point directed over a person struggling in water. At what angle of slight should the pilot release a rescu...

Time of flight(T)=(2H/g)

Range(R)=u*T

R=430*1000/3600*(2*1200/9.8)

R=1869.21m

Now,

tan(theta)=H/R=0.64

Theta=32.62

Can three vectors not lying in a plane give zero resultant?

No, if three vectors do not lie in a plane, they cannot give zero resultant.

Explanation:

Let A, B and C be three vectors. If they give zero resultant, then

     A+B+C=0

or, A= -(B+C)

Hence, they will produce zero resultant, if A is equal to negative of vector (B+C). The vector (B+C) lies in the plane of B and C. Hence, A will be equal to negative of (B+C) if A, B and C all lie in a plane.

a ray reflected successively from two plane mirrors inclined at a certain angle undergoes a deviation of 300. Then the angle isa) 30    b) 60    c) 90    d 120

$BAD=x$      , ABD=y 

Here AD and BD are Normal lines,

OBA=90y      OAB=90x

ΔOAB;

θ+90y+90x=180

              x+y=θ

Total deviation is 2(90x)+2(90y) 

                             =3602(x+y)

                             =3602θ

Here from the question deviation angle is...

A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell...

1.      How can a spherical wavefront be converted into plane wavefront?

If a point source of light is kept at the focus of a convex lens, we can get parallel waves emerging out from the lens, which form a plane wavefront.

Join the following pairs of sentences using although/though/even though and despite/in spite of as in the example:a. He is a millionaire. He lives in a simple house.b. The weather was extremely bad...

a. Although he is a millionaire, he lives in a simple house.

In spite of his richness, he lives in a simple house.

b. Even though the weather was extremely bad, the pilot landed the plane safely.

Despite the bad weather, the pilot landed safely.

c. Although we study in the same college, we hardly see each other.

Despite studying in the same college, we hardly see each other.

d. Although it rained heavily, we enjoyed our holiday.

In spite of heavy rain, we enjoyed our holiday.

e. Although I...

Why it is necessary to use shoulder straps and a lap belt in a car while a lap belt is sufficient in a plane, even though a plane moves much faster than a car?