Q30 of 119 Page 159

In a typical Indian Bugghi (a luxury cart drawn by horses), a wooden plate is fixed on the rear on which one person can sit. A bugghi of mass 200 kg is moving at a speed of 10 km/h. As it overtakes a school boy walking at a speed of 4 km/h, the boy sits on the wooden plate. If the mass of the boy is 25 kg, what will be the new velocity of the bugghi?

Ans.


Initial momentum of the school boy before sitting = 4×25

= 100 kg km/h


Initial momentum of the bugghi before the boy sat on it


= 10×200 = 2000 kg km/h


Total initial momentum of the bugghi and the school boy


= 2000+100 = 2100 kg km/h


Let the new velocity of the bugghi be v km/h.


Final momentum of the bugghi after the school boy sat on it


= v×(100+25)


= 125v kg km/h


Applying conservation of total linear momentum,


⇒ 125v = 2100




∴ The new velocity of the bugghi after the process of sitting = 28/3 km/h


More from this chapter

All 119 →
28

Two persons each of mass m are standing at the two extremes of a railroad car of mass M resting on a smooth track (figure 9-E10). The person on left jumps to the left with a horizontal speed u with respect to the state of the car before the jump. Thereafter, the other person jumps to the right, again with the same horizontal speed u with respect to the state of the car before his jump. Find the velocity of the car after both the persons have jumped off.


 29

Figure (9-E11) shows a small block of mass m which is started with a speed v on the horizontal part of the bigger block of mass M placed on a horizontal floor. The curved part of the surface shown is semicircular. All the surfaces are frictionless. Find the speed of the bigger block when the smaller block reaches the point A of the surface.


 31

A ball of mass 0.50 kg moving at a speed of 5.0 m/s collides with another ball of mass 1.0 kg. After the collision the balls stick together and remain motionless. What was the velocity of the 1.0 kg block before the collision?

 32

A 60 kg man skating with a speed of 10 m/s collides with a 40 kg skater at rest and they cling to each other. Find the loss of kinetic energy during the collision.