A ball with a mass of 400 g400g is projected vertically by a spring loaded contraption. The spring in the contraption has a spring constant of 25 (kg)/s^225kgs2 and was compressed by 3/7 m37m when the ball was released. How high will the ball go?

1 Answer
Sep 26, 2017

Potential Energy stored in spring if it compressed by x meter
U=1/2 kx^2U=12kx2
where k="spring constant"=spring constant
x="Compression"x=Compression
m=0.4 kgm=0.4kg
U=1/2(25)(3/7)^2=(25xx9)/(2xx49)U=12(25)(37)2=25×92×49

if spring release the ball will get kinetic energy which is equal to the potential energy of spring. (Conservation of energy)
K=1/2mv^2=(25xx9)/(2xx49)K=12mv2=25×92×49
=>0.4v^2=(25xx9)/(49)0.4v2=25×949
=>v^2=(25xx9)/(0.4xx49)=(25xx9xx10)/(4xx49)v2=25×90.4×49=25×9×104×49
=>v=sqrt((25xx9xx10)/(4xx49)v=25×9×104×49
=>v=(5xx3xxsqrt10)/(2xx7)=15/14sqrt10v=5×3×102×7=151410

To find the height we use Newton's Equation
v^2=u^2+2asv2=u2+2as
where u=u=initial velocity =15/14sqrt10=151410
v="final velocity"=0v=final velocity=0
a=-g="acceleration due to gravity"=-9.8m/s^2a=g=acceleration due to gravity=9.8ms2

Hence 0^2=(15/14)^2xx10-2(9.8)s02=(1514)2×102(9.8)s
s=(15/14)^2(10/(2xx9.8))=2250/3841.6=0.585 ms=(1514)2(102×9.8)=22503841.6=0.585m