Assertion: if air resistance is considerd then time to ascent and time of desent will be different.
Reason: Magnitudes of acceleration will be different in upwards and downward motion.

Assertion: Air above the fire at some distance is hotter than the air below it at the same distance. Reason: Air surrounding the fire carries more heat upwards than downwards.

A player throws a ball upwards with an initial speed of 29.4 ms^(-1) (a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ? (c) 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. (d) To what height does the ball rise and after how long does the ball return to the player's hands ? (Take g = 9.8 ms^(-2) and neglect air resistance).

A player throws a ball upwards with an initial speed of 29.4 ms^(-1) . (a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ? (c) 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. (d) To what height does the ball rise and after how long does the ball return to the player’s hands ? (Take g = 9.8 ms^(-2) and neglect air resistance).

Illustrate the acceleration-time graph under different conditions.

A player throwsa a ball upwards with an initial speed of 29.4 ms^(-1) . (i) What is the direction of acceleration during the upwared motion of the ball? (ii) What are the velocity and acceleration of the ball at the highest point of its motion? (iii) Choose the x=0 and t=0 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 positive, velocity and acceleration of the ball during its upward, and downward motion. (iv) To what height does the ball rise and after how long does the ball return to the player's hand?( Take g =9.8 ms^(-2) , and neglect air resistance).

A player throwsa a ball upwards with an initial speed of 29.4 ms^(-1) . (i) What is the direction of acceleration during the upwared motion of the ball? (ii) What are the velocity and acceleration of the ball at the highest point of its motion? (iii) Choose the x=0 and t=0 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 positive, velocity and acceleration of the ball during its upward, and downward motion. (iv) To what height does the ball rise and after how long does the ball return to the player's hand?( Take g =9.8 ms^(-2) , and neglect air resistance).

A player throwsa a ball upwards with an initial speed of 29.4 ms^(-1) . (i) What is the direction of acceleration during the upwared motion of the ball? (ii) What are the velocity and acceleration of the ball at the highest point of its motion? (iii) Choose the x=0 and t=0 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 positive, velocity and acceleration of the ball during its upward, and downward motion. (iv) To what height does the ball rise and after how long does the ball return to the player's hand?( Take g =9.8 ms^(-2) , and neglect air resistance).

A : In the presence of air resistance, if the ball is thrown vertically upwards then time of ascent is less than the time of descent. R : Force due to air friction always acts opposite to the motion of the body.