If an object with a mass of $2 k g$ $2 kg$ changes speed from $2 \frac{m}{s}$ $2 m/s$ to $5 \frac{m}{s}$ $5m/s$ , by how much does its kinetic energy change?

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Answer 1 · 2017-01-06T11:29:42

$11 J$ $11J$

Kinetic energy is calculate dby the formula $K E = \frac{1}{2} m v^{2}$ $" "KE=1/2mv^2$

so in this case

$m = 2 k g, v_{1} = 2 m s^{- 1}, v_{2} = 5 m s^{- 1}$ $m=2 kg,v_1=2 ms^(-1),v_2=5ms^(-1)$

$K E_{1} = \frac{1}{2} \times 2 \times 2^{2} = 4 J$ $KE_(1)=1/2xx2xx2^2=4 J$

$K E_{2} = \frac{1}{2} \times 2 \times 5^{2} = 25 J$ $KE_2=1/2xx2xx5^2=25 J$

$Delta KE=KE_2-KE_1=25-4=11 J$

If an object with a mass of 2 kg 2kg2 kg changes speed from 2 m/s2ms2 m/s to 5m/s5ms 5m/s, by how much does its kinetic energy change?