Answer: 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
[tex]v' = \sqrt{\frac {48 \times 2}{12}}\sqrt 8 = 2.8 m/s[/tex]
Thus, at speed 2.8 m/s, the sled would have twice amount of kinetic energy.
