Answer:
a) 30J
Explanation:
use formula first find K.E with both speeds
K.E. = 1/2 m v2
and then
work done= change in kinetic energy
30 Joule of work is to be done.
Option: a
Explanation:
Given, mass of snowboard = 5 Kg
Initial speed = 2 m/s, Final speed = 4 m/s, Work done = ΔE
Where, ΔE= change in kinetic energy
Solution:
[tex]\text { Kinetic Energy (initial) }=\frac{1}{2} \times \mathrm{mv}^{2}[/tex]
[tex]\text { Kinetic Energy (initial) }=\frac{1}{2} \times 5 \mathrm{Kg} \times(2 \mathrm{m} / \mathrm{s})^{2}[/tex]
[tex]\frac{1}{2} \times 20 \mathrm{Kg} \cdot \mathrm{m}^{2} / \mathrm{s}^{2}[/tex] = [tex]10 \mathrm{Kg} \cdot \mathrm{m}^{2} / \mathrm{s}^{2}[/tex]
[tex]\text { Kinetic Energy (final) }=\frac{1}{2} \times m v^{2}[/tex]
[tex]\frac{1}{2} \times 5 \mathrm{Kg} \times(4 \mathrm{m} / \mathrm{s})^{2}[/tex]
[tex]\frac{1}{2} \times 5 \mathrm{Kg} \times 16 \mathrm{m}^{2} / \mathrm{s}^{2}[/tex]
[tex]\frac{1}{2} \times 80 \mathrm{Kg} \cdot \mathrm{m}^{2} / \mathrm{s}^{2}[/tex]
[tex]40 \mathrm{Kg} \cdot \mathrm{m}^{2} / \mathrm{s}^{2}[/tex]
Work done = ΔE = Kinetic Energy (final) - Kinetic Energy (initial)
Work done = ΔE = 40 J - 10 J work done = ΔE = 30J
