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Kinetic equation problem

Kinetic equation problem-example-1
User Mark Finkle
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1 Answer

25 votes
25 votes

Use the kinematic formula


{v_2}^2 - {v_1}^2 = 2a\Delta x

where
v_1,v_2 are initial/final velocities,
a is acceleration, and
\Delta x is displacement. We're given
a=-5.00(\rm m)/(\rm s^2) and
\Delta x=15.0\,\rm m, and the car comes to a stop so
v_2=0. Solve for
v_1.


-{v_1}^2 = 2\left(-5.00(\rm m)/(\rm s^2)\right) (15.0\,\mathrm m) \\\\ ~~~~ \implies {v_1}^2 = 150.(\rm m^2)/(\rm s^2) \\\\ ~~~~ \implies v_1 = \sqrt{150.(\rm m^2)/(\rm s^2)} \approx \boxed{12.2 (\rm m)/(\rm s)}

User Gareth Bowen
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2.9k points