Answer:
16 J
Explanation:
It is given that,
Work done, W = 2 J
A spring is stretched by 2.0 cm from its equilibrium length
We need to find how much more work will be required to stretch it an additional 4.0 cm.
Let k is the spring constant of the spring. When W = 2J, and x = 2 cm, then energy required to stretch the spring is :

The energy required to stretch the spring from 2 cm to additional 4 cm i.e. 2+4= 6 cm.

So, the required work done is 16 J.
Answer:
c. The coefficient of kinetic friction is less than the coefficient of static friction
Explanation:
When the box finally does break loose. Then the component of the box weight which is parallel to the board weight parallel component, is equal to the
.

For the box to acce;erate thee must be non-zero net force acting on the box parallel to the board. Or we can say,

Therefore the force of kinetic friction must be less than the force of static friction. Thus,

Answer: <u>Centrifugal Force </u>
Explanation:
The force that pulls out from the center on a body in circular motion is called centrifugal force and it increases with acceleration. Centrifugal force results in strong outward pull on your vehicle.
When glass is rubbed with a dry cloth, the friction creates charged static electricity; this in turn attracts small non charged particles of dust. The simplest way to put it, the dry cloth creates a static charge that attracts non charged dust particles.