Question

A body dropped from a height h with an initial speed zero strikes the ground with a velocity 3 kilometre per hour another body of the same mass is dropped from the same height h with initial speed u is equal to 4 kilometre per hour find the final velocity ii body with which it strikes the ground

Answer 1

Answer:

5km/hr

Explanation:

From third equation of motion, v  

′

 

=u  

′

 

+2as where v and  u are final & initial velocity, a is acceleration, s is distance.

For first case v  

1

​

=3 km/h,u  

1

​

=0,a  

1

​

=g,s  

1

​

=?

s  

1

​

=  

36×36×20

9×100

​

m

For second case v  

2

​

=?,u  

2

​

=4 km/h,a  

2

​

=g=10 m/s

s  

1

​

=s  

2

​

=  

36×36×20

9×100

​

 m

So, v  

2

2

​

=  

3600×3600

16×1000×1000

​

+  

20×36×36

2×10×9×100

​

 

Or, v  

2

​

=5 km/hr