#19 A 2100 kg truck travel north at 41 km/h turns east and accelerates to 51 km/h.
(a) What is the change in the truck’s kinetic energy? What are the
(b) magnitude
(c) direction of the change in its momentum?

Respuesta :

Answer

given,

mass of truck = 2100 Kg

velocity in  north  direction = 41 km/h

                     = 41 x 0.278 m/s

                     = 11.398 m/s

velocity in  north  direction = 51 km/h

                     = 51 x 0.278 m/s

                     = 14.178 m/s

a) Change in K.E

          = [tex]\dfrac{1}{2}m(V_f^2-V_i^2)[/tex]

          = [tex]\dfrac{1}{2}\times 2100\times (14.178^2-11.398^2)[/tex]

          = 7.453 x 10⁴ J

b) Change in momentum

         [tex]\Delta P = m(v_f-V_1)[/tex]

         [tex]\Delta P = 2100\times (14.178 - 11.398)[/tex]

         [tex]\Delta P = 5838\ kg.m/s[/tex]

c) Direction of momentum

        [tex]\theta = tan^{-1}(\dfrac{P_y}{P_x})[/tex]

        [tex]\theta = tan^{-1}(\dfrac{11.398}{14.178})[/tex]

        [tex]\theta = 38.796^0[/tex]