If an object with a mass of $2 kg$ changes speed from $14 m/s$ to $15m/s$ , by how much does its kinetic energy change?

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Answer 1 · 2016-01-21T19:25:35

Change in kinetic energy can be calculated using
$Delta E_k=1/2m(v_f^2-v_i^2)$

Kinetic energy is calculated using:

$E_k=1/2mv^2$
Change in $E_k$ is just final minus initial, or
$Delta E_k=1/2mv_f^2-1/2mv_i^2$

which factors to

$Delta E_k=1/2m(v_f^2-v_i^2)$

So, in this case,

$Delta E_k=1/2 2kg(15^2-14^2)$

$Delta E_k=29J$

If an object with a mass of 2 kg 2 kg changes speed from 14 m/s14 m/s to 15m/s 15m/s, by how much does its kinetic energy change?