Question

A ball is kicked from a location 7, 0, −8 (on the ground) with initial velocity −11, 19, −5 m/s. The ball's speed is low enough that air resistance is negligible. (a) What is the velocity of the ball 0.4 seconds after being kicked? (Use the Momentum Principle!) v = Incorrect: Your answer is incorrect. m/s

Answer 1

Answer:

$\vec{v} =$

Explanation:

given,

location of the ball ⟨7,0,−8⟩

initial velocity of the ball ⟨-11,19,−5⟩

time = 0.4 s

speed of the ball = ?

using Momentum Principle

change in momentum = Force x time

$m \vec{v} - m \vec{u}= \vec{F}\times \Delta t$

$\vec{v} =\vec{u} + \dfrac{\vec{F}}{m}\times \Delta t$

Net force acting in this case will be equal to force due to gravity because air resistance is negligible.

F_net = F_g = ⟨0 ,-9.8 m , 0⟩

now,

$\vec{v} = + \dfrac{}{m}\times (0.4-0)$

$\vec{v} = +$

$\vec{v} =$

hence, the velocity of the ball 0.4 s after being kicked is equal to $\vec{v} =$