Question

lesson 2.4: kinetic energy and motion

1. what type of energy is associated with the motion of an object?
2. what two factors determine the kinetic energy of an object.
3. a 4.00 g bullet is travelling at 140 m/s. determine the kinetic energy of the bullet.
4. if a particle of mass 2.3 x 10^{-6} kg has a kinetic energy of 5.7 x 10^{-2} j, what is its speed?
5. a curling rock, sliding down the ice at a speed of 2.40 m/s, is determined to have a kinetic energy of 57.6 j. what is the mass of the curling rock?

Explanation:

Step1: Convert mass units

Given mass of bullet \(m = 4.00\ g=4.00\times10^{- 3}\ kg\), speed \(v = 140\ m/s\). The formula for kinetic energy is \(K=\frac{1}{2}mv^{2}\).

Step2: Substitute values into formula

Substitute \(m = 4.00\times10^{-3}\ kg\) and \(v = 140\ m/s\) into \(K=\frac{1}{2}mv^{2}\).

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Answer:

The kinetic energy of the bullet is \(39.2\ J\).