![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
The resultant force of each force on an object moving in a uniform circular motion must be a centripetal force Why is it wrong
Centripetal force itself is not a force. We can only say what provides centripetal force, not what force is centripetal force
Must the resultant force on an object moving in a uniform circular motion be a centripetal force
By all means
Why can friction provide centripetal force? Why does the car need centripetal force when turning? Why is the external force equal to the external force when an object moves in a uniform circular motion Centripetal force required?
Because the speed is a vector, when the car turns at a constant speed, the direction of the speed vector changes and produces acceleration (note that the size of the speed remains unchanged when generating this acceleration). For the sake of good hearing, physicists call this acceleration centripetal acceleration. At the same time, according to Niu er's law, the mass multiplied by the acceleration is equal to the combined external force acting on the object
Why is it wrong that the acceleration of an object in circular motion must point to the center of the trajectory? Such as title
The acceleration of an object in circular motion must point to the center of the track. This sentence is wrong. The acceleration of an object in uniform circular motion must point to the center of the track. The acceleration of an object in variable speed circular motion must not point to the center of the track. The normal acceleration ay, only changes the speed direction, does not change
Uniform circular motion, the speed changes, why? For example, when a car accelerates on a straight road, the speed changes, but the direction does not change!
Did you talk about this on the second day of junior high school?
Speed is divided into size and direction
In uniform circular motion, the speed is constant because it is uniform
But the direction of velocity is always tangent to the radius, so it is changing all the time
Therefore, the change of velocity in uniform circular motion is actually the change of velocity direction
Why do we say that uniform circular motion is a variable acceleration motion, the speed has not changed, but only the direction. Why is it still an accelerated motion
When there is acceleration, we call it variable speed motion
Speed is a vector. Any change in size and direction indicates a change in speed
The change of speed does have the theory of increase and decrease, but I don't know how much change can be collectively referred to as "increment". For decrease, the increment is negative. For example, there is also the theory of "negative growth" in life
Similarly, I don't know about the change of speed. Sometimes it is collectively referred to as "variable acceleration", which is just a saying
RELATED INFORMATIONS
- 1. There are four line segments with the length of 1.2.3.4 respectively. The probability that any three of them will form a triangle is
- 2. If the three sides of an obtuse triangle are a + 1, a + 2 and a + 3, the value range of a is __
- 3. Four conditions for friction Is it 1. Objects contact and squeeze each other 2. The contact surface is not smooth 3. Relative motion or relative motion trend between objects 4. There is elasticity between objects
- 4. Are the objects on the horizontal conveyor belt subject to friction The conveyor belt is horizontal with an object moving forward at a uniform speed. Is this object subject to friction? If it's moving from rest to uniform speed, is there friction
- 5. As shown in Figure 2, a disk rotates at a uniform speed around the vertical axis passing through the center in the horizontal plane, and a small object on the disk is stationary relative to the disk and moves with the disk. The centripetal force on the object is correct in the following statement: a A. The direction of the centripetal force points to the center of the disc B. the direction of the centripetal force is the same as the speed direction of the object C. The centripetal force direction is parallel to the rotating shaft D. the centripetal force direction remains unchanged The disc rotates counterclockwise
- 6. When the wood block with mass of M = 1kg is stationary on the platform with height of H = 1.2m, the dynamic friction coefficient between the wood block and the platform As shown in the figure, the wood block with mass of M = 1kg is still at the height of H = 1.2m Dynamic friction coefficient between wood block and platform on platform μ= 0.2, with horizontal thrust f = 20n, Remove the wood block when it has a displacement of S1 = 3M, and fly out of the platform when it slides again and S2 = 1m, Find the speed of the wooden block when it falls to the ground? ( )
- 7. As for friction, the correct one in the following statement is () A. The direction of sliding friction is always opposite to the direction of motion of the object B. Sliding friction always hinders the relative motion between objects C. The magnitude of the friction force must be proportional to the pressure between the contact surfaces D. The direction of friction can be perpendicular to the direction of motion of the object
- 8. Why should the trajectory of the particle with the longest flight time in a magnetic field be tangent to the boundary of the magnetic field
- 9. The wood block with mass m is placed on a smooth horizontal plane, and the bullet with mass m is fired in the horizontal direction at velocity V0 and finally remains in the wood block and moves with the wood block in V A,FL=1/2Mv2 B.Fs=1/2mv2 C.Fs=1/2mv02-1/2(M+m)v2 D.F(L+s)=1/2mv02-1/2mv2 The wood block with mass m is placed on a smooth horizontal plane, and the bullet with mass m is fired in the horizontal direction at velocity V0 and finally remains in the wood block and moves with the wood block in V. It is known that when the bullet is stationary relative to the wood block, the wood block advances L, and the depth of the bullet entering the wood block is s. if the resistance F of the wood block to the bullet is constant, then
- 10. A horizontal disc with radius r rotates at a constant angular velocity W. a person with mass m wants to go from the edge of the disc to the center of the disc. What is the attack of the disc on him? The answer is - 1 / 2MR ^ 2W ^ 2
- 11. The centripetal force of an object in uniform circular motion is a constant force, right?
- 12. Right triangle area formula
- 13. How to prove the formula of the relationship between the radius of the inscribed circle and the trilateral of a right triangle?
- 14. How to determine the direction of friction in physics?
- 15. Determine the direction of friction Many books explain that a bicycle moves at a uniform speed when it is stepped on by people, so the front wheels are subject to backward friction The front wheel does not rotate forward as the rear wheel does. Why is the rear wheel backward and the front wheel ahead? thank
- 16. Why can the direction of friction be perpendicular to the direction of motion of an object?
- 17. Does the hand of an object moving at a uniform speed on the conveyor belt have the effect of friction,
- 18. The object with mass m is stationary on the horizontal desktop, and the dynamic friction coefficient between the object and the desktop is μ， Now push the object with a horizontal force to accelerate the object for a period of time. Remove the force, and the object will slide for a period of time and then stand still. Given that the total distance of the object is s, what is the work done by this thrust to the object?
- 19. It is known that the circumference of an isosceles triangle is 30 cm and the length of one side is twice the length of the other. Find the length of its three sides
- 20. 7. The object with mass m is pulled by a string through a smooth small hole, and makes a uniform circular motion on a smooth horizontal plane. When the tension is a certain value f, it rotates When the tensile force is a certain value f, the rotation radius is R. when the tensile force gradually increases to 6F, the object still moves in a uniform circular motion. At this time, the radius is R / 2, then the work done by the tensile force on the object is: () A、0 B、FR C、3FR D、5FR/2