![]() ![]() The key is that the particle "tries" to move forward (i.e. You say two things that are not necessarily consistent: first "when provided the velocity it tries to move forward" then "the particle is just forward of its initial position". At every instant the arm exerts a force toward the axis that is of exactly the right magnitude to keep the particle moving on a circle. In this case you have a perfectly rigid arm connecting the "particle" to the center point. Usually we're talking about an "idealized" experiment. The velocity changing and the force changing happens practically simultaneously over infinitesimal time intervals. we are thinking in terms of infinitesimal changes that then add up over time. You are thinking "Move forward, then force reacts later, then velocity changes later." But when we think about velocities, accelerations, etc. But more importantly, you seem to be thinking in finite, sequential steps. Won't this slows down the particle and makes it stop? But it is said it won't affect its velocity, How?Īnd now you seem to be thinking about uniform circular motion. So there is a component of force along velocity direction. This makes the angle between radius and velocity more than 90 degrees. This force is along the radius, but in shortest interval of time the particle is just forward from its initial position. This forward motion give rise to centripetel force. ![]() There has to be some force tangent to the circular path in order to speed the particle up. ![]() So we are not talking about uniform circular motion here. As soon as the particle is provided the velocity, it tries to move forward. When particle is about to start its motion there is no centripetal force. However, it is still possible in circular motion for the velocity magnitude to change if there are force components that are tangential (perpendicular to the radius). In uniform circular motion the velocity magnitude stays constant, and the net force is entirely centripetal. It looks like you are getting confused with uniform circular motion and circular motion in general. the magnitude of the velocity) is constant, no work is being done and the energy remains constant.It is said that in circular motion velocity of particle is perpendicular to centripetal force, so velocity of particle won't gets affected. In uniform circular motion, only the direction of the velocity is changing, because the force is at right angles to the movement. The kinetic energy depends only on the magnitude of the velocity and not on its direction. As the work done on an object in uniform circular motion is 0, there is no change in kinetic energy for the object in uniform circular motion. Work is also defined as the change in kinetic energy. Therefore, we conclude that no work is being done on an object in uniform circular motion. If we apply this to our equation for work: ![]() This gives us the situation where the angle,, between the force and the direction of motion is 90°. Even though the object is constantly changing direction, the motion at any instant is always tangential to the circle. One of the features of circular motion, is that the centripetal force is always directed into the centre of the circle that is the path for the object. This now results in the equation for work becoming: As force and displacement are vectors, we correctly say that it is only the component of the force in the direction of motion that contributes to the work being done. Work is defined as the force ( ) applied to move an object some displacement ( ). ![]()
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