Answer:Zero
Explanation:
Given
mass of ball
If the ball is thrown upward then at maximum point velocity of ball is zero because ball is no longer able to move upward
Momentum(P) of a particle is given by
Therefore at the highest point momentum is zero .
Answer:
The number of calories needed is 6c.
Explanation:
The amount of energy needed to raise the temperature
of water of mass
is
where is the specific heat capacity of water.
Putting in numbers into equation (1), we get:
which is the number of calories needed.
Given data:
* The mass of the book is 2 kg.
* The initial height of the book is 0.78 m.
* The final height of the book is 2.1 m.
Solution:
(A). The work done by the gravity on the book is,
where m is the mass, g is the acceleration due to gravity, h_i is the initial height and h_f is the final height,
The work is done in moving the object in upward direction where as the gravitational force is acting in the down ward direction. Thus, the value g (acceleration due to gravity) is taken as negative in this case.
Substituting the known values,
Thus, the work done by the gravitational force is -25.9 J.
(B). The work done by the hand on the moving the book is,
Thus, the work done by the hand on the book is 25.9 J.