4. A coconut falls from a tree and lands on the ground 2 s later. What is the final velocity and height of the tree?

vf=19.6

h=19.6

FROM FIRST EQUATION that is vf=vi+gt

then vf = 0+9.8*2=19.6m/s

FROM SECOND EQUATION that is H=vi*t+1/2gt²

then H=0*2+1/2*9.8*2²=19.6

W

g

=mgs (1)

Change in velocity of coconut is,

E=

2

1

m(u−v)

2

=−

2

1

m(v)

2

(2)

Now, total work done on coconut is equal to change in kinetic energy hence,

W

a

+W

g

=

2

1

mv

2

where, W

a

is  work done by air resistance.

Using (1) and (2), we get

W

a

the answer is a. hope this .

the inner core.

good luck: )

klicker