Answer:
Option C = 30 j
Explanation:
Given data:
mass of snowboard = 5 Kg
Initial speed = 2 m/s
final speed = 4 m/s
work done = ΔE= ?
ΔE= change in kinetic energy
Solution:
Formula:
K.E (initial) = 1/2 × mv²
K.E (initial) = 1/2 × 5 Kg . (2m/s)²
K.E (initial) = 1/2 × 20 Kg.m²/s²
K.E (initial) = 10 Kg.m²/s² or 10 J
Kg.m²/s² = J
K.E (finial) = 1/2 × mv²
K.E (finial) = 1/2 × 5 Kg . (4m/s)²
K.E (finial) = 1/2 × 5 Kg . 16 m²/s²
K.E (finial) = 1/2 × 80 Kg.m²/s²
K.E (finial) = 40 Kg.m²/s² or 40 J
work done = ΔE = K.E (finial) - K.E (initial)
work done = ΔE = 40 J - 10 J
work done = ΔE = 30 J
