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. A car is moving with uniform velocity 40 m/sec.It is stopped in 4 sec by applying a force of 1300 Newton through its brakes.calculate (a) change in momentum(b)retardation of car(c)the mass of car. |
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Answer» soln: heregiven:initial velocity(u)= 40m/sfinal velocity(v) = 0 m/s [ the sudden apply of the brake cause the final velocity to be 0.]FORCE APPLIED(f) = 1300 Ntime taken(t) = 4snow,a) change in momentum= be xwe know that,F= change in momentum/timeor, 1300= x/4or, 1300*4 = XSO, x= 5200 kg*m/sb) retardation of the car(a)=a= (v-u)/tor, a= 0-40/4so, a= -10∴ retardation of teh car= 10 m/s^2 [ no need to write -10m/s^2 as retardation already means negative acceneration.]c) the mass of the car=we know that,F= maor, 1300= m* (-10)or, 1300/ (-10)= m∴ mass of the car(m)= -130 kgExplanation: |
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