Yes it is work because when you throw a ball, you transfer energy to it and it moves.
Average speed = (total distance) / (total time)
Average speed = (4+7+1+2 blox) / (1 hour)
<em>Average speed = 14 blocks/hour</em>
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I'm gonna go out on a limb here and take a wild guess:
I'm guessing that there's another question glued onto the end of this one, and it asks you to find either her displacement or her average velocity. I'm so sure of this that I'm gonna give you the solution for that too. If there's no more question, then you won't need this, and you can just discard it. I won't mind.
Average velocity = (displacement) / (time for the displacement)
"Displacement" = distance and direction from the start point to the end point, regardless of how she got there.
Displacement = (4E + 7W + 1E + 2W)
Displacement = (5E + 9W)
<em>Displacement = 4 blocks west</em>
Average velocity = (4 blocks west) / (1 hour)
<em>Average velocity = 4 blocks/hour West</em>
1) 15 / 12 = 1.25 ratio
2) to increase acceleration 1.25 times (with same F, or same engine) you have to lower mass 1.25 times
3) 1515/1.25 = 1212 kg
choose A
Answer:
Distance= 2.3864m
Explanation:
So that the balance is in equilibrium parallel to the floor, we must match the moment each man makes with respect to the pivot point.
In many cases the point of application of force does not coincide with the point of application in the body. In this case the force acts on the object and its structure at a certain distance, by means of an element that transfers that action of this force to the object.
This combination of force applied by the distance to the point of the structure where it is applied is called the moment of force F with respect to the point. The moment will attempt a rotation shift or rotation of the object. The distance from the force to the point of application is called the arm.
Mathematically it is calculated by expression:
M= F×d
The moment caused by the first man is:
M1= 75kg × (9.81m/s²) × 1.75m= 1287.5625 N×m
The moment caused by the second man must be equal to that caused by the first by which:
M2= 1287.5625 N×m= 55kg × (9.81m/s²) × distance ⇒
⇒distance= (1287.5625 N×m)/( (55kg × (9.81m/s²) )= 2.3864m
At this distance from the pivot point, the second should sit down so that the balance is balanced parallel to the ground.
Answer:
B) Friction
Explanation:
Friction is a force that acts when an object is sliding along a surface. Microscopically, this force is due to the fact that the two surfaces are not perfectly smooth, but they have "imperfections" that cause a force that opposes the motion of the object.
For an object sliding on a flat surface, the force of friction has magnitude:
where
is the coefficient of kinetic friction
m is the mass of the object
g is the acceleration of gravity
The direction of the force of friction is always opposite to the direction of motion of the object.
In reality, friction also acts if the object is at rest and it is pushed by a force; in this case, we talk about static friction, and its magnitude is
where 
is called coefficient of static friction, and it is generally larger than the coefficient of kinetic friction.
