<span>None of the light passes through it; some of the light is absorbed as heat but most is reflected off the surface. This is how you see </span>objects. reflected light from them hits your eye. (Opaque means not transparent)
Answer:
The maximum static frictional force is 40N.
Explanation:
When an object of mass M is on a surface with a coefficient of static friction μ, there is a minimum force that you need to apply to the object in order to "break" the coefficient of static friction and be able to move the object (Called the threshold of motion, once the object is moving we have a coefficient of kinetic friction, which is smaller than the one for static friction).
This coefficient defines the maximum static friction force that we can have.
So if we apply a small force and we start to increase it, the static frictional force will be equal to our force until it reaches its maximum, and then we can move the object and now we will have frictional force.
In this case, we know that we apply a force of 40N and the object just starts to move.
Then we can assume that we are just at the point of transition between static frictional force and kinetic frictional force (the threshold of motion), thus, 40 N is the maximum of the static frictional force.
-- If the work is done to make the object move faster, then
the work done becomes kinetic energy of the object.
-- If work is done on the object but it doesn't move any faster,
then there must be friction holding it back. In that case, the work
that's done just to keep the object moving becomes heat, in the
places where the friction acts on it.
Answer:
energy is the capacity to do work
