Physics - Kinematics Question

[sciencebooks]

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Question: Is it possible for the path of an object whose velocity vector has a constant magnitude and direction to have a shape other than a straight line?

Now, I remember that the answer is yes, such as in a parabola. But I can't seem to recreate the drawing. It's basically that at all points, the vx vector is pointed in the same direction. But doesn't the vy vector go from pointing up to point down after decreasing to zero at the top of the trajectory?

 

[shaboobly]

Question: Is it possible for an object whose velocity vector has a constant magnitude and direction to have a shape other than a straight line?

Now, I remember that the answer is yes, such as in a parabola. But I can't seem to recreate the drawing. It's basically that at all points, the vx vector is pointed in the same direction. But doesn't the vy vector go from pointing up to point down after decreasing to zero at the top of the trajectory?

yea you can always break a velocity from a trajectory into components using some trig. also in uniform circular motion the particle is moving in a circle with constant velocity around it.

 

[sciencebooks]

yea you can always break a velocity from a trajectory into components using some trig. also in uniform circular motion the particle is moving in a circle with constant velocity around it.

Yeah, but in UCM, it's direction is constantly changing as there's centripetal acceleration toward the center. That's why I'm tripped up on the "constant magnitude AND direction" part, lol.

 

[shaboobly]

Yeah, but in UCM, it's direction is constantly changing as there's centripetal acceleration toward the center. That's why I'm tripped up on the "constant magnitude AND direction" part, lol.

an object with constant velocity will remain in a straight line path with the same velocity as long as there are no external forces acting. this means once there is a force, the object will accelerate and change direction, depending on the direction and magnitude of the force (for all we know the force could be in the same direction as the velocity and the only thing that will change is the velocity, not direction). in uniform circular motion the magnitude of velocity is going to be the same all the way around the circle and the direction of it will change because there are forces acting on the object and which is why the object has the centripetal acceleration. the opposite to centripetal force is the centrifugal force and this is basically the same as the normal force. if you add these two forces on the object and the result is 0, you achieve uniform circular motion and the velocity is constant.

the only way to keep the same direction is if there are no external forces.

 

[stevenz]

Nope. It's not possible. If velocity is constant (acceleration is zero), then objects travel along straight lines. This is a restatement of Newton's first law.

 

[LoLCareerGoals]

Question: Is it possible for an object whose velocity vector has a constant magnitude and direction to have a shape other than a straight line?

Have you read the question you put down? I guess if you are currently reviewing from the same book or something it might be obvious what you mean, but I was a bit wtfed.

Sure it is possible. It can shaped like a car, or a plane, or a boat. A number of things can move in a constant direction and maintain the same speed. So the answer is yes if it has good cruise control.

 

[Silo004]

No, if velocity is zero then the magnitude is zero and the direction is not a straight line, but a point.

 

[shaboobly]

No, if velocity is zero then the magnitude is zero and the direction is not a straight line, but a point.

which means the object isnt moving and thus isnt kinematic, but static. the question was referring to kinematics.

 

[sciencebooks]

Have you read the question you put down? I guess if you are currently reviewing from the same book or something it might be obvious what you mean, but I was a bit wtfed.

Sure it is possible. It can shaped like a car, or a plane, or a boat. A number of things can move in a constant direction and maintain the same speed. So the answer is yes if it has good cruise control.

Hahaha, whoops. Edited.