Question

If momentum decrease by 20%, K.E. will decrease by

Answer 1

Answer:K.E. will decrease by 36%.

Explanation:

let's say,

Initial K.E. =(p)∧2/(2m)     ; [where p= mv = momentum]

momentum decrease= 20%

new momentum= 0.8 p

final K.E.= (0.8 p)∧2 / (2m) = (0.64)p∧2 / (2m)  ;

decrease in K.E. = {[p∧2/(2m)]-[(0.64)p∧2/(2m)]}

                            = (0.36)p∧2/(2m)

% decrease in K.E. = decrease in K.E./ initial K.E.

                                = 36%