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A force of 70 N is applied to a 28 kg rock causing it to slow down from 25 m/s to 15 m/s, a change in velocity of 10 m/s. How long was that force applied?

Respuesta :

Answer: 4 s

Explanation:

Given

The applied force is 70 N

mass of the rock is 28 kg

initial velocity [tex]u=25\ m/s[/tex]

final velocity [tex]v=15\ m/s[/tex]

Deceleration provided by force is

[tex]a=-\dfrac{70}{28}=-2.5\ m/s^2[/tex]

using the equation of motion

[tex]v=u+at\\\Rightarrow 15=25-2.5t\\\Rightarrow 2.5t=10\\\Rightarrow t=4\ s[/tex]

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