Question
Wed December 28, 2011 By:

a truck of mass 5000kg traveling at 40m/s is brought to rest by applying its brakes. the truck comes to rest after traveling 20m after application of brakes. what is the kinetic energy of the truck?

Expert Reply
Thu December 29, 2011

Here v=0 m/s and u= 40m/s

S= 20 m

V2-u2= 2as

-(20)2 =2x20a

-400/40=a

-10m/s2= a

K.E= ½ m v2

=1/2x 5000x40 x40                 =                      5000x20x40               = 4x 106J

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