When the box IS on the shelf 2m above the ground,
its potential energy is
(weight) x (height) = (3 N) x (2 m) = 6 joules .
THAT's the work you have to do, to lift the box up to there.
Answer:

Explanation:
The centripetal acceleration of the child, which is moving by uniform circular motion, is given by

where
v = 5 m/s is the tangential speed of the child
r = 1.2 m is the radius of the circular path
Substituting the numbers into the equation, we find

Answer:
v = 17.66 m/s
Explanation:
As we know that the lower end of the pole is fixed in the ground and it start rotating about that end
so here we can say that the gravitational potential energy of the pole will convert into rotational kinetic energy of the pole about its one end
so we have

so we have

now we have


now the speed of the other tip of the pole is given as


Answer:
option A
Explanation:
given,
angular speed is constant
initial distance = r
final distance (r')= 2 r
initial linear velocity = v
final linear velocity = v'
we know,
v = r ω......................(1)
where r is the distance
ω is the angular speed
now,
v' = r' ω
v' = 2 r ω
v' = 2 v
hence, the linear velocity doubles.
The correct answer is option A
Answer:
Mollusks
Explanation:
The shear concentration of fossilized mollusks can be explained by the ability of their shells which are comprised primarily of calcium, allowing the hard shells remain and become fossilized long after the animal has decomposed.