A ball is thrown upward with an initial velocity of 20m/s
.a) How long is the ball in the air?
b) What is the greatest height reached by the ball?
c) When is the ball 15m above the ground?

Respuesta :

Ball is 2.04 sec in the air after it will undergoes free fall, Max height 20.14 m and after  0.99 sec the ball 15m above the ground.

What are the equations of motion?

  • First Equation of Motion : v = u + a t.
  • Second Equation of Motion : s = u t + 1/2 a t ²
  • Third Equation of Motion : v ²= u² + 2 a s.

The most basic principles of an object's motion are described by kinematics equations of motion. These equations control an object's motion in 1D, 2D, and 3D. They make it simple to compute expressions like an object's position, velocity, or acceleration at different points in time.

At max height, V=0.

So:

v=u+at

0=20–9.8t

9.8t=20

t=2.04 secs…

Ball is 2.04 sec in the air after it will undergoes free fall.

s = ut + ½ at^2

=20* 2.04  - (9.8 * 2.04² / 2)

= 40.8 - 20.39

= 20.41 m

Max height 20.14 m

ball 15m above the ground:

v^2 = u^2 + 2 as.

= 20^2 - 2 * 9.8 * 15

= 400- 294

=106

v = [tex]\sqrt{106}[/tex] =10.3 m/s

v=u+at

10.3 = 20 -9.8 * t

t = (20 -10.3) /9.8 = 0.99 sec

at 0.99 sec the ball 15m above the ground.

To learn more about acceleration refer,

https://brainly.com/question/27821888

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