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## Homework Statement

A projectile of mass 5 kg is fired with an

initial speed of 80 m/s at an angle of 75◦ with

the horizontal. At the top of its trajectory,

the projectile explodes into two fragments of

masses 3 kg and 2 kg . The 2 kg fragment

lands on the ground directly below the point

of explosion 2.5 s after the explosion.

The acceleration of gravity is 9.81 m/s2 .

Find the magnitude of the velocity of the

3 kg fragment immediatedly after the explo-

sion. Answer in units of m/s.

Find the distance between the point of firing

and the point at which the 3 kg fragment

strikes the ground. Answer in units of km.

How much energy was released in the explo-

sion? Answer in units of kJ.

## The Attempt at a Solution

~pi = ~pf

m1 ~v1 = m2 ~v2 + m3 ~v3

m1 v1^{ = m2 vx2^i + m2 vy2 ^j ¡ m3 vy3 ^j

Vx=m1/m2 (VcosO)

Y=(vsin0)^2/(2*9.8)

Vy3=(y-(1/2)(g)(t^2))/2.5

Vy2=m3/m2(Vy3)

sqrt(Vx2^2+Vy2^2)

magnitude V2x=80.7314m/s

Where did i go wrong?