A spring gun of spring constant 90 N cm^(-1) is compressed 12 cm by a ball of mass 16 g. If the trigger is pulled, the velocity of the ball is

A spring gun of spring constant 90 N cm^(-1) is compressed 12 cm by a

1.	A spring gun of spring constant 90 N cm^(-1) is compressed 12 cm by a ball of mass 16 g. If the trigger is pulled, the velocity of the ball is
Answer» `50 m s^(-1)` `40 MS^(-1)` `60 m s^(-1)` `90 ms^(-1)` Solution :Here , `m = 16 g = 16 xx 10^(-3) kg` `k = 90 N cm^(-1) = 90 xx 10 Nm^(-1)` `x = 12 cm = 12 xx 10^(-2) m` According to the law of CONSERVATION of energy, `1/2 mv^2 = 1/2 kx^2 " or " V^2 = (kx^2)/(m)` or `v = xsqrt(k/m) (12 xx 10^(-2)m) sqrt((90 xx 100 Nm^(-1))/(16 xx 10^(-3) kg)) = 90 ms^(-1)`. Thus the velocity of the ball `90 ms^(-1)`.