Una niña está empujando un baúl. El PESO del baúl es de 230 N y el roce es de 50 N, la niña sólo logra ejercer una fuerza de 30
1 answer:
Answer:
Su padre necesita aplicar una fuerza de 20 newtons en la misma dirección que la fuerza aplicada por su hija.
Explanation:
Asúmase que el baúl se mueve en una superficie horizontal. La fuerza de rozamiento dada por el problema es la fuerza de rozamiento estático máximo, se requiere una fuerza externa antiparalela a la fuerza de rozamiento estático máximo para que el baúl se empiece a mover. La ecuación de equilibrio de fuerzas horizontales sobre el baúl es:
Donde:
- Fuerza externa aplicada sobre el baúl, medida en newtons.
- Fuerza de rozamiento estático máximo, medida en newtons.
Se despeja la fuerza externa:
Si , entonces:
Si la niña solo logra ejercer una fuerza de 30 newtons, su padre necesita aplicar una fuerza de 20 newtons paralela a aquella fuerza.
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Given :
A 120 kg box is on the verge of slipping down an inclined plane with an angle of inclination of 47º.
To Find :
The coefficient of static friction between the box and the plane.
Solution :
Vertical component of force :
Horizontal component of force(Normal reaction) :
Since, box is on the verge of slipping :
Therefore, the coefficient of static friction between the box and the plane is 1.07.
Hence, this is the required solution.
Explanation:
A) To prove the motion of the center of mass of the cylinders is simple harmonic:
System diagram for given situation is shown in attached Fig. 1
We can prove the motion of the center of mass of the cylinders is simple harmonic if
where aₓ is acceleration when attached cylinders move in horizontal direction:
<h3>PROOF:</h3>rotational inertia for cylinders is given as:
-----(1)
Newton's second law for angular motion is:
∑τ = Iα ------(2)
For linear motion in horizontal direction it is:
∑Fₓ = Maₓ ------ (3)
By definition of torque:
τ = RF --------(4)
Put (4) and (1) in (2)
from Fig 3 it can be seen that fs is force by which the cylinders roll without slipping as they oscillate
So above equation becomes
------ (5)
As angular acceleration is related to linear by:
Eq (5) becomes
---- (6)
aₓ shows displacement in horizontal direction
From (3)
∑Fₓ = Maₓ
Fₓ is sum of fs and restoring force that spring exerts:
----(7)
Put (7) in (3)
[/tex] -----(8)
Using (6) in (8)
--- (9)
For spring mass system
----- (10)
Equating (9) and (10)
then (9) becomes
(The minus sign says that x and aₓ have opposite directions as shown in fig 3)
This proves that the motion of the center of mass of the cylinders is simple harmonic.
<h3 /><h3>B) Time Period</h3>Time period is related to angular frequency as:
