Answer:
[tex]\huge\boxed{\sf m=1.96 \ kg}[/tex]
Explanation:
Speed = v = 15 m/s
Kinetic Energy = K.E. = 220 J
Mass = m = ?
[tex]\displaystyle K.E. = \frac{1}{2} mv^2[/tex]
Put the givens
[tex]\displaystyle 220 =\frac{1}{2} m(15)^2\\\\\times 2 \ to \ both \ sides\\\\220 \times 2 = m (225)\\\\440 = m (220)\\\\Divide \ 220\ to \ both \ sides\\\\440/225 = m\\\\1.96 \ kg=m\\\\m=1.96 \ kg\\\\\rule[225]{225}{2}[/tex]