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a constant net force

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From Wikipedia

Net force

In mechanics, the net force (also known as resultant force) is the overall force acting on an object when all the individual forces acting on the object are added together.

Informal introduction

A force in mechanics is a concept that has both a size and a direction. The net force acting on an object is the sum of the forces onto the object, taking into account both their sizes, and their directions. For example, if an object has two forces acting on it, with equal sizes but in opposite directions, then the net force will be zero (technically: a null vector). If instead the forces are of equal size and in the same direction, then the net force is equal to twice either force. The net force can be seen as a hypothetical force that, acting on an object, has the same effect as all the actual forces combined.

Definition

The net force Fnet = F1 + F2 + … is a vector produced when two or more forces { F1, F2, … } act upon a single object. It is calculated by vector addition of the force vectors acting upon the object.

Examples

When force A and force B act on an object in the same direction (parallel vectors), the net force (C) is equal to A + B, and points in the same direction as A and B.

When force A and force B act on an object in opposite directions (180 degrees between then - anti-parallel vectors), the net force (C) is equal to |A - B|, and points in the direction of whichever one has greater absolute value ("greater magnitude").

(Note: The illustration assumes that the object, in this case a square, has no center of mass and can be treated like apoint.)

When the angle between the forces is anything else, then the net force can be visualized using the parallelogram rule.

For example, see Figure 3. This construction has the same result as moving F2 so its tail coincides with the head of F1, and taking the net force as the vector joining the tail of F1 to the head of F2. This procedure can be repeated to add F3 to the resultant F1 + F2, and so forth. Figure 4 is an example.



From Yahoo Answers

Question:If an object of constant mass experiences a constant net force, it will have a constant (a) Velocity (b) Speed (c) Acceleration (d) Position (e) More than one of these

Answers:It will have constant velocity and speed because it it is acted on by constant force no change in the velocity and speed of the object, when there is no change in the velocity acceleration will be zero, and the object will not acceleration therefore the answer is (e)

Question:A constant net force acting on an object that is free to move will produce a constant: A. Speed B. Velocity C. Displacement D. Acceleration

Answers:D. Acceleration Newton's Second Law: Force = mass * acceleration So, if you have a constant force, it will produce a constant acceleration (assuming the object's mass doesn't change). Hope this helps!

Question:A constant net force of 430 N is applied upward to a stone that weighs 31 N. The upward force is applied through a distance of 2.0 m, and the stone is then released. To what height, from the point of release, will the stone rise? Unless otherwise directed, assume that air resistance is negligible.

Answers:The potential energy of the stone at its maximum height H is 31 H { Since P.E =mgh} To increase the P.E a force of [430 + 31] was applied and moved it through a distance of 2m. Work done by this force is F*d = 461*2 = 922 J 31 H = 922 => H = 29.74 m =====================================

Question:A constant net force of 395 N is applied upward to a stone that weighs 35 N. The upward force is applied through a distance of 2.0 m, and the stone is then released. To what height, from the point of release, will the stone rise? Assume that air resistance is negligible.

Answers:Use conservation of energy in this problem. Work done on stone = Work absorbed by the stone Work done on stone = 395 * 2 = 790 joules Work absorbed by stone = 35(h) where h = height at which stone will rise from the point of release Therefore, 35(h) = 790 h = 22.57 meters Hope this helps.

From Youtube

Force and Constant Velocity :This is a physics problem where an object has constant velocity and you need to determine the force acting on it based on the idea that objects at constant velocity have a net force of zero.