A0.10-kilogram ball dropped vertically from a
height of 100 meter above the floor bounces back
to a height of 0.80 meter. the mechanical energy
lost by the ball as it bounces is
a. 0.080j
b.
0.20 j
c. 0.303
d. 0.78)

B

Explanation:

P.E = mass × acceleration due to gravity  × height

initial P.E = 0.10  × 9.81 × 10  ( in question 100 m is a typing error , it must be     1 .00 m )

               = 0.981J

final P.E = 0.10   × 9. 81  × 0.80

              = 0.7848 J

HENCE mechanical energy lost = 0. 981 - 0.7848

                                                     = 0.1962 J

                                                     =   0.20 J

HENCE  B

their crystal patterns have been disrupted by stress

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s