If a body slows down to a stop, it has negative acceleration (deceleration), and when it accelerates negatively to a stop, it will have zero velocity.
velocity may be zero or may not be zero i.e. if the object may continue to move with uniform velocity.
When an object moves with uniform velocity, its slope is zero. This means the object is not accelerating and is moving at a constant speed in a straight line.
Only instantaneously. If an object is being negatively accelerated, it will be slowing down. If the negative acceleration continues to act on the body, it may, at some point have zero velocity because it has come to a stop, but still have the force acting on it. In the next instant, the object will then be accelerated in another direction. This isn't a "trick" answer. It is just offered to explain a situation in mechanics where an object with some initial velocity is experiencing negative acceleration due to some decelerating force. The dynamics are pretty simple and easy to get your head around if you think about them.
The velocity does not change direction or magnitude. The object 1) may not be moving, or it 2) may be moving at a constant velocity. In the case of the latter, that means it's moving in the same direction and at a constant speed.
At that moment, its vertical velocity is zero. Its horizontal velocity may or may not be zero, i.e., it may be moving sideways as well.
velocity may be zero or may not be zero i.e. if the object may continue to move with uniform velocity.
velocity may be zero or may not be zero i.e. if the object may continue to move with uniform velocity.
When an object moves with uniform velocity, its slope is zero. This means the object is not accelerating and is moving at a constant speed in a straight line.
Only instantaneously. If an object is being negatively accelerated, it will be slowing down. If the negative acceleration continues to act on the body, it may, at some point have zero velocity because it has come to a stop, but still have the force acting on it. In the next instant, the object will then be accelerated in another direction. This isn't a "trick" answer. It is just offered to explain a situation in mechanics where an object with some initial velocity is experiencing negative acceleration due to some decelerating force. The dynamics are pretty simple and easy to get your head around if you think about them.
In classical physics, if a force (e.g. the sum of all forces) acts on a body, the body cannot have zero acceleration (unless the body has infinite mass), since a = F/m. The velocity on the other hand may be zero, since a(t) = v'(t).
A horizontal line parallel to speed axis indicates that the body is moving at a constant speed i.e. it's speed doesn't change with passage of time. The body may have zero or non zero acceleration, but it will always have non zero velocity. But, that doesn't mean that body's velocity is constant and it is not accelerated. For example in uniform circular motion the speed of body remains constant but velocity changes due to change in the direction of motion. Also there is acceleration towards center of circle called centripetal acceleration which changes the direction of velocity. For this acceleration a force should act towards the center called centripetal force. If speed is constant then the force, if present, must act in direction perpendicular to the immediate direction of motion i.e. perpendicular to the tangent drawn at any point on the path of motion.
Not necessarily. The graph of instantaneous velocity versus time may or may not have a Y-axis intercept of zero. It depends on the initial conditions and motion of the object. If the object starts from rest, then the initial velocity is zero, and the graph will have a Y-axis intercept at zero.
The velocity does not change direction or magnitude. The object 1) may not be moving, or it 2) may be moving at a constant velocity. In the case of the latter, that means it's moving in the same direction and at a constant speed.
Vf = Vi + a t
It's not. If you speed is constant (but not zero), then your velocity won't be zero, either.You may be confusing this with the following: If your VELOCITY (not your speed) is constant, then your ACCELERATION is zero. Acceleration refers to how quickly velocity changes, so if velocity doesn't change at all, acceleration is zero.
At that moment, its vertical velocity is zero. Its horizontal velocity may or may not be zero, i.e., it may be moving sideways as well.
Velocity is a vector quantity that includes both magnitude (speed) and direction. Thus, velocity can be zero if there is no motion, but speed is the magnitude of velocity and cannot be negative. Speed is always a positive scalar quantity, so it cannot be zero if there is any motion at all.