List of practice Questions

A car moving along a straight highway with speed of 126 \(\text{km}\;\text h^{-1}\) is brought to a stop within a distance of 200 \(\text m\). What is the retardation of the car (assumed uniform), and how long does it take for the car to stop ?
A player throws a ball upwards with an initial speed of 29.4 m \(\text s^{-1}\). 
  1. What is the direction of acceleration during the upward motion of the ball ?
  2. What are the velocity and acceleration of the ball at the highest point of its motion ?
  3. Choose the x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
  4. To what height does the ball rise and after how long does the ball return to the player’s hands ? (Take g = 9.8 \(\text m \;\)\(\text s^{-2}\) and neglect air resistance).
Read each statement below carefully and state with reasons and examples, if it is true or false ; 
A particle in one-dimensional motion 
  1. with zero speed at an instant may have non-zero acceleration at that instant 
  2. with zero speed may have non-zero velocity, 
  3. with constant speed must have zero acceleration, 
  4. with positive value of acceleration must be speeding up.
Figure 2.15 gives a speed-time graph of a particle in motion along a constant direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude? In which interval is the average speed greatest ? Choosing the positive direction as the constant direction of motion, give the signs of v and a in the three intervals. What are the accelerations at the points A, B, C and D ?
speed-time graph of a particle in motion along a constant direction