Force on an object being dragged

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In summary: F cos (theta) because the suitcase is moving with constant velocity.So what you need to do is solve for F in the equationmg - F sin (theta) = F cos (theta).Your answer will be (60.16 kg) (9.8 m/s²) / (1.54 + sin(52.1°)) = 79.3 N.
  • #1
jj8890
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Homework Statement


You drag a suitcase of mass 9.2 kg with a force of F at an angle 52.1 degrees with respect to the horizontal along a surface with kinetic coefficient of friction 0.54. The acceleration of gravity is 9.8 m/s^2.
If the suitcase is moving with constant velocity 1.65 m/s, what is F ?


Homework Equations


F=ma


The Attempt at a Solution


F=ma

a = 0

FcosΘ - Friction = (9.2)(0)
F - µR = 0

F - (0.54)((9.2)(9.8)-mgsinΘ)) = 0
F- (0.54)(90.16 - 9.2(9.8)sin52.1) = 0
F - 0.54(19.016) = 0
F = 10.268 N

but this is not right..I think that I am doing something wrong...Any help would be great. Thanks
 
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  • #2
this should be enough...

If the object moves with constant velocity then NET force on it is zero.
REMEMBER THE KEYWORD "NET" HERE...

Fcos theta - friction= zero

>fcos theta = frictional force.
>f cos theta=48.68
>f=48.68/cos 52.1
>f=48.68/.614
>f=79 N
 
Last edited:
  • #3
physixguru said:
this should be enough...

If the object moves with constant velocity then NET force on it is zero.
REMEMBER THE KEYWORD "NET" HERE...

Fcos theta - friction= zero

>fcos theta = frictional force.
>f cos theta=48.68
>f=48.68/cos 52.1
>f=48.68/.614
>f=79 N

The frictional force depends on F and theta. If you pull upwards the suitcase, the force that the suitcase exerts on the ground will be smaller, and therefore the friction will decrease.
with theta = 60 your answer would have F > mg and the suitcase flying up in the air.:smile:

The force with which you pull upward on the suitcase is F sin(theta), so the frictional force is 0.54 (mg - F sin(theta))
 

Related to Force on an object being dragged

1. What is force on an object being dragged?

Force on an object being dragged is the strength or energy that is applied to an object when it is being pulled or pushed along a surface. It is a vector quantity that has both magnitude and direction.

2. What factors affect the force on an object being dragged?

The force on an object being dragged can be affected by various factors such as the weight and mass of the object, the friction between the object and the surface it is being dragged on, and the applied force.

3. How is the force on an object being dragged calculated?

The force on an object being dragged is calculated using the formula F = μN, where F is the force, μ is the coefficient of friction, and N is the normal force. It can also be calculated using Newton's Second Law, F = ma, where m is the mass of the object and a is the acceleration.

4. How does the angle of the drag affect the force on an object?

The angle of the drag, or the direction in which the object is being pulled, can affect the force on the object. If the angle is perpendicular to the surface, the force will be the greatest. As the angle becomes more parallel to the surface, the force decreases.

5. Can the force on an object being dragged ever be zero?

Yes, the force on an object being dragged can be zero if the object is not moving or if the applied force and the opposing forces, such as friction, cancel each other out. This is known as a state of equilibrium.

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