Question

Name:

Answer 1

Answer:

1.a) 1 kJ

1.b) 4 kJ

     ratio 1:4

1.c) 4 times as before

2.a)  3.33 m/s2

Explanation:

1.a) bicycle's velocity =Displacement/time

                                   =100/20 m/s

                                   =5 m/s

bicycler's KE =1/2 *mass*(velocity)^2

                      =1/2*80*5^2

                       =1000 J = 1 kJ

1.b) bicycle's new velocity =200/20 m/s

                                   =10 m/s

bicycler's new KE =1/2*80*10^2

                             =4000 J = 4 kJ

Ratio= KE 1 :KE new

        = 1 :4

1.c)  when bicycler's speed was doubled it increased the KE by 4 times (2^2). because In KE we consider the square of the speed , so the factor we increase the speed , the KE will get increased with the square value of it

ex : speed is triple the prior value , then the KE is as 3^2 times as before. that is 9 times

2.a) car acceleration = (20-0)/6 m/s2

                                  = 3.33 m/s2