Question

1)a vehicle of mass m is moving on a rough horizontal surface with a momentum p .if the coefficient of friction bet the tyres and the road is U then the stopping distance is                           2)two masses 5kg and 3kg are suspended from the ends of an unstrechable light string passing over a frictionless pulley .when the masses are released the thrust on the pulley is          3)a block of 2 kg is suspended from the ceiling thru a massless spring of spring constant k=100N/m.what is the elongation of the spring?if anothe r1 kg is added to the block what would be the further elongation?                                                                                                                PLZZ put the q.no b4 ansering

Answer 1

1. $\frac{ (\frac{p}{m}) ^{2} }{2Ug}$

2. a = 2g/8 = g/4  (a = acceleration of masses) 
    5g - T = 5*g/4   (T = tension in the string)
    T = 15g/4 
    Thrust = 2T = 7.5g = 75N

3.a. 20 = 100.x₁
       x₁ = 0.2m 
   b. 30 = 100.x₂
        x₂ = 0.3m 
    so further elongation = x₂ - x₁ = 0.1m