possible for a body to have zero velocity and nonzero accelerationby Mitchtwitchita Tags: acceleration, body, nonzero, velocity 

#1
Sep2108, 06:29 PM

P: 191

Is it possible for a body to have zero velocity and nonzero acceleration. I would have to say no because acceleration is the time rate of change of velocity. So, if velocity isn't changing, how can there be an acceleration. Is this answer accurate?




#2
Sep2108, 08:16 PM

Mentor
P: 28,837

Zz. 



#3
Sep2108, 09:09 PM

P: 191

Gravity!!! Then I guess, I would have been wrong. So, I would have to say now that a body is unable to travel with a constant acceleration and a timevarying velocity. Would you say that this is a correct assumption?




#4
Sep2108, 09:46 PM

Sci Advisor
P: 8,007

possible for a body to have zero velocity and nonzero accelerationForce of gravity between the ball and earth = mg, where m is the mass of the ball where g is a constant, which represents the "effect of the gravitational mass of the earth". Newton's 2nd law, F=ma, where F is the total force on the ball where m is again the mass of the ball where a is the acceleration of the ball in response to F. Since gravity is the only force on the ball, we combine the force of gravity and Newton's 2nd law as follows: mg=ma. Hence a=g. So the acceleration of the ball is constant in magnitude and direction. When you throw the ball upwards, a is downwards and opposite to the velocity, so the ball "decelerates". At the top of the trajectory, the ball has instantaneous 0 velocity. Then it moves downwards, a is still downwards but now in the same direction as the velocity, and the ball "accelerates". (Sorry I used "accelerate" in two slightly different ways here, hence the bolding for the first technically correct use, and the quotes over the second colloquial use.) 



#5
Sep2208, 10:58 AM

Sci Advisor
P: 2,507




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