Newton’s first law is motion. For example, an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Answer:
D.None of these
Explanation:
The derivation of acceleration formula:
Let us call the 5kg mass 
and the 4kg mass 
. If the tension in the string is 
then for the mass
(1). 
<em>(the negative sign on the right side indicates that acceleration is downwards)</em>
And for the mass
(2). 
<em> (the acceleration is upwards, hence the positive sign)</em>
Solving for in the 2nd equation we get:
,
and putting this into the 1st equation we get:
Back to the question:
Using the formula for the acceleration we find
which is the acceleration that none of the given choices offer. Also, the acceleration of the two blocks is the same, because if it weren't, the difference in the instantaneous velocities of the objects would cause the string to break. Therefore, these two reasons make us decide that none of the choices are correct.
That's false.
The definition of momentum is (mass) x (speed), so they must be multiplied.
"20,000 kg-m/s" has the correct units resulting from multiplication, but the number could only be the result of division.
We can define power as the rate of doing work, it is the work done in unit time. The SI unit of power is Watt (W) which is joules per second (J/s). Sometimes the power of motor vehicles and other machines are given in terms of Horsepower (hp) which is approximately equal to 745.7 watts.
Power is the rate at which a force is applied to an object for example.current wire
