I dont need the work shown I just need the answers in the

-/4 points HRW10 9.P.055. Notes Ask Your Teach 5.0 kg block with a speed of 3.5 m/s collides with a 10 kg block that has a speed of 1.5 m/s in the same direction. After he collision, the 10 kg block travels in the original direction with a speed of 2.0 m/s (a) What is the velocity of the 5.0 kg block immediately after the collision? m/s (b) By how much does the total kinetic energy of the system of two blocks change because of the collision? (c) Suppose, instead, that the 10 kg block ends up with a speed of 4.7 m/s. What then is the change in the total kinetic energy? (d) Account for the result you obtained in (c).

Solution

Masses of blocks m = 5 kg

                         M = 10 kg

Initial velocities u = 3.5 m/s

                     U = 1.5 m/s

Velocities after collision v = ?

                                   V = 2 m/s

From law of conservation of linear momentum ,

mu + MU = mv + MV

5(3.5) +10(1.5) = 5 v +10(2)

32.5 = 5v +20

   5v = 32.5 - 20

      = 12.5

    v = 2.5 m/s

(b).Change in kinetic energy during colliison =[(1/2) mu ² +(1/2)MU ²] -[(1/2)mv ² +(1/2)MV ²]

                                                                = [(0.5 x5x3.5 ² )+(0.5x10x1.5 ²)]-[(0.5x5x2.5 ²)+(0.5x10x2 ²)]

                                                                = [30.625+11.25]-[15.625 +20]

                                                                = 6.25 J

(c).

Masses of blocks m = 5 kg

                         M = 10 kg

Initial velocities u = 3.5 m/s

                     U = 1.5 m/s

Velocities after collision v = ?

                                   V = 4.7 m/s

From law of conservation of linear momentum ,

mu + MU = mv + MV

5(3.5) +10(1.5) = 5 v +10(4.7)

32.5 = 5v +47

   5v = 32.5 - 47

      = -14.5

    v = -2.9 m/s

Change in kinetic energy during colliison =[(1/2) mu ² +(1/2)MU ²] -[(1/2)mv ² +(1/2)MV ²]

                                                                = [(0.5 x5x3.5 ² )+(0.5x10x1.5 ²)]-[(0.5x5x(-2.9) ²)+(0.5x10x4.7 ²)]

                                                                = [30.625+11.25]-[21.025 +110.45]

                                                                = -89.6 J

Kinetic energy is increases in colliision.