# Physics-Kinetic energy

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Two 2.0 g bullets are fired with speeds of 40.0 m/s and 80.0 m/s, respectively. What are their kinetic energies? Which bullet has more kinetic energy? What is the ratio of their kinetic energies?

A car has kinetic enery of 4.32* 10^5 when traveling at a speed of 23m/s. What is its masss?

I have around 12 problems of these and I am not very good with formulas. Please someone just do these and then I will be able to do the other ones, but please step by step.

• Physics-Kinetic energy -

the only formula you will need for both of these questions is :
E = 0.5mv^2
E = kinetic energy (J)
m = mass of object (kg)
v = velocity of object (m/s)

you should be able to go from here, just sub in the values.

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