Question

A rubber cord catapult has cross-sectional area

25mmand initial length of rubber cord is 10c.
Its is stretched to 5cm and then released to
project a missile of mass 5gm. Taking
Yubber = 5x108N/m² velocity of projected
missile is :
(1) 20ms -
(2) 100ms
(3) 250ms
(4) 200ms)​

Answer 1

Potential energy stored in the rubber cord catault will be converted into kinetic energy of mass
2
1
​
mv
2
=
2
1
​

L
YAl
2

​

where l=5×10
−2
m, A=25×10
−6
m
2
, L=10×10
−2
m, m=5×10
−3
kg
⇒v=
mL
YAl
2

​

​

v=
5×10
−3
×10×10
−2

5×10
8
×25×10
−6
×(5×10
−2
)
2

​

​

v=250ms
−1