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  1. A 20-kg child is tossed up into the air by her parent. The child is 2 meters off the ground traveling 5 m/s.

Circle one: KE / GPE / both


Show your work for finding the values of each type of energy the object has

Verified Answer :

SapphireMoon

The child has kinetic energy (KE) because she's moving, and gravitational potential energy (GPE) because she's off the ground.
KE = 1/2mv²
KE = 1/2 (20 kg)(5 m/s)²
KE = 50 J

Ug (gravitational potential energy) = mgy
Ug = (20)(9.8)(2) = 392 J

Make sense? Need anything else?

Answer: Option (c) is the correct answer.

Explanation:

When the child is tossed up into the air then she gains kinetic energy as the child has moved from its initial position.

It is given that mass is 20 kg, velocity is \(5 m/s^{2}\), and height is 2 m.

Calculate the kinetic energy of child as follows.

             kinetic energy = \(\frac{1}{2}mv^{2}\)

                                      = \(\frac{1}{2}20 kg \times (5 m/s)^{2}\)

                                      = \(10 kg \times 25 m^{2}/s^{2}\)

                                      = \(250 kg m^{2}/s^{2}\)

Also, when child falls off the ground then she will have gravitational potential energy.

Calculate gravitational potential energy of child as follows.

            Potential energy = m × g × h

                                         = \(20 kg \times 9.8 m/s^{2} \times 2 m\)

                                         = \(392 kg m^{2}/s^{2}\)

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