Question

What is the work that must be done to increase the velocity of a bike that weighs 200 kg

from 20 m/s to 30 m/s.​

Answer 1

Explanation:

Work done = Change in kinetic energy.

$initial \: ke \: = \frac{1}{2} m {v}^{2} \\ = \frac{1}{2} \times 200 \times {20}^{2} \\ = 40000 \: joules$

$final \: ke = \frac{1}{2} m {v}^{2} \\ = \frac{1}{2} \times 200 \times {30}^{2} \\ = 90000 \: joules$

Therefore,

By work-energy theorem,

Work done= Change in kinetic energy

=final KE - initial KE

=50,000 J

Answer 2

Answer:

50,000J

Explanation:

Mass (m): 200 Kg

initial (u) : 20 m/s

final. (v) : 30m/s

work done,

W=1/2m(v^2-u^2)

=1/2*200{(30)*2-(20)*2}

=100(900-400)

=100(500)

=50,000J