Question

A car of mass 2400kg moving with a velocity of 20m/s is stopped in 10 sec on applying brakes. Calculate the retardation and the retarding force?

Answer 1

m=2400*1000g
u=20m/s
v=0
t=10seconds
retardation=u-v/t
=-20/10
=-2m/s^2

Answer 2

mass(m)= 2400 kg,       initial velocity(u)- 20m/s,   final velocity(v) =0     time taken(t)= 10s         retardation= ?     force=?

we can say thar retardation is negative acceleration

(i)by using first equation of motion,we get

v=u +at

0= 20+aX10

0= 20+10a

-20 = 10a

-20/10= a

-2= a

thus, retardation= 2m/s2

(ii) f= ma

f= 2400 X (-2)

= -4800N

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