Question

75) The work to be done to stop a cat of mass 1200 kg and moving at a speed of 36 Km/h is​

Answer 1

Answer:

Mass of car= 1200 kg

Speed of car (initial)= 36 kmph

= 36*5/18 m/s

= 10 m/s

Now,

Work done= Change in kinetic energy

= 1/2 m( v1^2-v2^2)

=1/2 *1200(0-100)

= -600*100 J

= -60000 J

= -60 kJ

Answer 2

Answer:

given mass=1200 kg

initial speed (u)= 36 km/h

speed must be written in SI unit

therefore speed=36km/h=10m/s

final speed v =0(when car stops)

we know that work done = change in kinetic energy = 1/2m(v^2-u^2)

therefore work done = -60000J=-60 KJ