Question

A bomb at rest explodes into three fragments. Two fragments fly off at right angles to each other.These two

• A. 14 m/s
• B. 15 m/s
• C. 18 m/s
• D. 16 m/s

Answer 1

The correct option is B 15 m/s

The initial momentum is 0

Initial momentum = final momentum

Final momentum:

Resultant momentum for the two is.

Mass is constant and depends not on the direction.

${12}^2+9^2=225$

The resultant velocity = $\sqrt{2}25$ = 15 m/s

Since the mass is equal we have.

Momentum = 15m

Let the velocity of the third one be v

The final momentum is = mv + 15m

0 = mv + 15m

-15m = mv

v = - 15

The velocity of the third one is :

15 m/s