C.) <span>The total mass of an object can be assumed to be focused at one point, which is called its center of "Mass"
Hope this helps!</span>
Use conservation of momentum ;
m1u1 + m2u2 = m1v1 + m2v2
1200×15.6 + 0 = 2700v
v = 18720/2700
v = 6.933 or ~ 7 m/s
The free-body diagram is missing, but I assume the only forces acting on the box are the force F pushing the box, the weight of the object and the normal reaction of the surface.
Since the weight and the normal reaction acts in the vertical (y) direction, the only force acting on the box in the horizontal (x) direction is the horizontal component of the force F, which is given by

And so this is the net force in the x-direction.
<h3>1)</h3>
No,kinetic energy cannot be negative since its given by KE=mv²,mass cannot be negative and the square of speed cannot b negative.
<h3>2)</h3>
Yes,any force opposing motion or displacement does negative work. They are often referred to as resistive forces (friction,air resistance,drag...)
<h3>3)</h3>
Nope it does not, it just forces the object to move in a circular path known as a centripetal force. It can accelerate an object by changing it's direction but not it's speed.
<h3>4)</h3>
No it cannot,If an object is sliding on the table (assuming it is not an incline), then most probably that normal force cancels out the weights effect or assuming there is an incline, it cancels the weight's y component.
<h3>5)</h3>

The work done is zero
<h3>6)</h3>

The work is just the product of the magnitude of the force exerted and the displacement of the object.
<h3>7)</h3>

<h3>Work is decreasing but positive</h3>
<h3>8)</h3>

<h3>Work is zero</h3>
<h3>9)</h3>

<h3>Work is negative</h3>
I think this answer Yes, salt is the crystal we use to season our food. But in chemistry, salt is a term used to describe a compound made by joining a positively charged acid with a negatively charged base. Table salt is the compound sodium chloride. It's composed of a positively charged sodium atom and a negatively charged chloride atom.