Consider the motion diagram of a point particle shown in the figure below. (a) W
ID: 1654424 • Letter: C
Question
Consider the motion diagram of a point particle shown in the figure below. (a) What is the sign of the position of the particle at all times shown? (circle one) Positive (+) Negative (-) (b) What is the sign of the velocity of the particle at all times shown? (circle one) Positive (+) Negative (-) (c) What is the sign of the acceleration of the particle at all times shown? (circle one) Positive (+) Negative (-) (d) On the motion diagram, draw and label the position vector, velocity vector and acceleration vector of the particle at t = 2 s.Explanation / Answer
(a) The position of the particle at all times lies left to the origin. Therefore, the sign of all position will be negative. The displacement in all cases will be positive.
(b) Velocity is displacement divided by total time. Since displacement will always be positive, this implies, velocity is positive.
(c) The magnitude of velocity is decreasing, (because the magnitude of displacement is decreasing), therefore, the acceleration of the particle at all time will have a negative sign.
(d) At t= 2s, the direction of position and velocity is towards the right in the given figure. Acceleration is in the negative direction, towards the left. This -ve acceleration is also called as retardation.