A ball is thrown vertically upward with a speed of 19.0 m/s. (a) How high does it rise? m (b) How long does it take to reach its highest point? s (c) How long does the ball take to hit the ground after it reaches its highest point? s (d) What is its velocity when it returns to the level from which it started?

Respuesta :

Answer with Explanation:

We are given that

Initial speed=[tex]u=19 m/s[/tex]

a.[tex]g=9.8m/s^2[/tex]

Final velocity of ball=[tex]v=0[/tex]

[tex]v=u-gt[/tex]

g is negative because the ball is going against to gravity.

[tex]0=19-9.8t[/tex]

[tex]9.8t=19[/tex]

[tex]t=\frac{19}{9.8}=1.94 s[/tex]

[tex]s=ut-\frac{1}{2}gt^2[/tex]

Using the formula

[tex]s=19(1.94)-\frac{1}{2}(9.8)(1.94)^2[/tex]

[tex]s=18.4 m[/tex]

a.The ball rise upto height 18.4 m

b.It take 1.94 s to reach its highest point.

c.Initial velocity=0,s=18.4 m

[tex]s=ut+\frac{1}{2}gt^2[/tex]

[tex]18.4=0(t)+\frac{1}{2}(9.8)t^2[/tex]

[tex]18.4=4.9t^2[/tex]

[tex]t^2=\frac{18.4}{4.9}[/tex]

[tex]t=\sqrt{\frac{18.4}{4.9}}[/tex]

[tex]t=1.94 s[/tex]

[tex]v=u+gt[/tex]

Using the formula

[tex]v=0+9.8(1.94)=19 m/s[/tex]

Answer:

Explanation:

initial speed, u = 19 m/s

(a) Let it rises upto height h.

Use third equation of motion

v² = u² - 2 gh

where, v is the final velocity and it is zero.

0 = 19 x 19 - 2 x 9.8 x h

h = 18.4 m

(c) Let the ball takes time t to reach to the maximum height.

use first equation of motion

v = u - gt

0 = 19 - 9.8 x t

t = 1.94 s

(c) The time taken by the ball to reach to the ground = 2 x time to reach to maximum height

T = 2 x t = 2 x 1.94 = 3.88 s

(d) When the ball reaches the ground, let the velocity is v.

Use third equation of motion

v² = u² - 2 gh

where, v is the final velocity

v² = 0 + 2 x 9.8 x 18.4

v = 19 m/s

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