Question

A ball of mass m is dropped from a height h1, and

after striking the ground the ball bounces back to a

height h2 (h2 < h1). If the ratio of the kinetic energy

while passing a point at height h (=

h2÷2 ) in the two

directions is 2 : 1, what is the ratio of h1 to h2?​

Answer 1

Answer:

since all the kinetic energy of ball in the air is lost into its P.E. at its peak.

so we can compare their K.E. by their P.E. at highest point.

initial K.E. =mgh  

1

​  

 

final K.E. =mgh  

2

​  

 

fractional loss in K.E.=  

mgh  

1

​  

 

mgh  

1

​  

−mgh  

2

​  

 

​  

=  

h  

1

​  

 

h  

1

​  

−h  

2

​  

 

​  

Explanation: