A student places her 500 g physics book on a frictionless ta-ble. She pushes the book against a spring, compressing the spring by 4.0 cm, then releases the book. What is the book’s speed as it slides away? The spring constant is 1250 N/m.

The book's speed is .

Explanation:

The expression of the elastic potential energy is as follows;

                                             .......... (1)

Here, PE is the elastic potential energy, k is the spring constant and x is the distance.

The expression for kinetic energy is as follows;

                                          ............ (2)

Here, m is the mass of the object and v is the speed.

According to the given problem, a student places her 500 g physics book on a frictionless table. She pushes the book against a spring, compressing the spring by 4.0 cm, then releases the book.  The elastic potential energy is converted into kinetic energy.

From (1) and (2),

PE=KE

Rearrange the above expression to calculate the book's speed.

Convert the distance x from cm to m.

x= 4 cm

x= 0.04 m

Convert the mass m from g to kg.

m= 500 g

m= 0.2 kg

Put x= 0.04 m, m= 0.2 kg and in the expression for book's speed.

Therefore, the book's speed is .

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.