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alingy1
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Homework Statement
Two masses, one of 20kg and the other of 40kg, are pushed using the same force on the same distance.
What is the ratio of the kinetic energy? (Kinetic energy of 20kg/kinetic energy of 40kg)
Homework Equations
Ek=mv^2
F=ma
v=at
The Attempt at a Solution
So, I found that the answer is 2/1. But the answer key says it's 1/1.
Here's my logic:
Let's say the constant force is 20N.
And that the time the force is applied is 3 seconds.
20kg:
F=ma
a=1m/s^2
v=3m/s
Ek=mv^2/2=90N
40kg:
F=ma
a=0,5m/s^2
v=1,5m/s
Ek=mv^2/2=45N
Ratio: 90/45=2/1
Why does the answer key say otherwise? Is my logic false somewhere? Please help. My exam is coming up soon.