Question

To determine the height of a flagpole, Abby throws a ball straight up and times it. She sees that the ball goes by the top of the pole after 0.50 s and then reaches the top of the pole again after a total elapsed time of 4.1 s. How high is the pole above the point where the ball was launched? (You can ignore air resistance.) To determine the height of a flagpole, Abby throws a ball straight up and times it. She sees that the ball goes by the top of the pole after 0.50 s and then reaches the top of the pole again after a total elapsed time of 4.1 s. How high is the pole above the point where the ball was launched? (You can ignore air resistance.) 16 m 13 m 18 m 26 m 10 m

Answer 1

`H = 10.05 m`

Step-by-step explanation:

If the stone will reach the top position of flag pole at t = 0.5 s and t = 4.1 s

so here the total time of the motion above the top point of pole is given as

`\Delta t = 4.1 - 0.5 = 3.6 s`

now we have

`\Delta t = (2v)/(g)`

`3.6 = (2v)/(9.8)`

`v = 17.64 m/s`

so this is the speed at the top of flag pole

now we have

`v_f - v_i = at`

`17.64 - v_i = (-9.8)(0.5)`

`v_i = 22.5 m/s`

now the height of flag pole is given as

`H = (v_f + v_i)/(2)t`

`H = (22.5 + 17.64)/(2) (0.5)`

`H = 10.05 m`