A12-kg sled is moving at a speed of 2.0 m/s. at which of the following speeds will the sled have twice as much kinetic energy? a. 2.8 m/s b. 4.2 m/s c. 6 m/s d. none of the above

2.8 m/s

Explanation:

Kinetic energy is the energy possessed by a body due to virtue of its motion - speed.

K.E. = 0.5 m v²

mass, m = 12 kg

speed, v = 2.0 m/s

K.E. = 0.5 × 12 × 2.0² = 24 J

For kinetic energy to be twice of the initial i.e. (24×2 = 48 J), the speed must be

48 J = 0.5 × 12× v'²

Thus, at speed 2.8 m/s, the sled would have twice amount of kinetic energy.

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

what type of charge does it have? negative