Why is no work done when you hold a book in place over your head? 1. a force is applied to the book, causing it to move. 2. a force is applied to the book, but there is no move why is no work done when you hold a book in place over your head? a force is applied to the book, causing it to move. 3. a force is applied to the book, but there is no movement. 4. the book has motion, but no force is applied to it. ment. the book has motion, but no force is applied to it.

3. A force is applied to the book, but there is no movement.

Explanation:

As we know that work done is defined as

Now we know that

F = force on the object

d = displacement of the object

Now since here book is hold at the head of the object and there is no displacement of the book

So the work done is zero here

as d = 0

So correct answer will be

3. A force is applied to the book, but there is no movement.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it