Question

A shot travelling at the rate of 200m/s is just able to pierce a plank of 5cm thick. What velocity is required to pierce a similar plank 20 cm thick.

Answer 1

Velocity need to pierce 5 cm plank = 200 m/s
Velocity need to pierce 1 cm plank = 200/5 m/s
Velocity required to pierce 20 cm plank = (200×20)/5
= 4000/5
= 800 m/s
So, The velocity required pierce 20 cm plank is 800 m/s.

Answer 2

Answer:

Velocity need to pierce 5cm plank=200m/sec

Velocity need to pierce 1cm plank=200/5 m/sec

Velocity need to pierce 20cm plank=(200x20)/5

=>4000/5

=>800m/s

So,The velocity needed pierce 20 cm plank is 800m/sec.