Advertisements
Advertisements
प्रश्न
What do you mean by the conservation of momentum? Briefly, explain the collision between two bodies and the conservation of momentum.
Advertisements
उत्तर
Conservation of momentum in case of a collision between two bodies means the total momentum before and after collision remains unchanged or conserved, provided no net force acts on the system.
Consider two bodies A and 8 having masses m1 and m, and initial velocities u1 and u, respectively. The bodies collide head on with each other and their collision lasts for t seconds. Suppose the velocities of A and 8 after collision are v1 and v, respectively. Assume that no external forces are acting on the bodies.
Rate of change of momentum of ball A = m1(v1 - u1)/t .
Rate of change of momentum of ball 8 = m1 (v1 - u1)/t .
If FAB is the force exerted by A on 8 and FBA is the force ex
Rated by 8 on A, we can write
FAB= m1(v1 - u1)/t .
FBA = m1 (v1 - u1)/t .
FAB = -FBA
m1(v1 - u1)/t = - m2(v2- u2)/t .
m1(v1 - u1) = - m2(v2- u2)
m1v1 +m2v2 = m1u1+m2u2
So total momentum after collision = total momentum before collision.
This proves conservation of momentum during collision.
APPEARS IN
संबंधित प्रश्न
A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m s–2. Calculate the initial thrust (force) of the blast.
A helicopter of mass 1000 kg rises with a vertical acceleration of 15 m s–2. The crew and the passengers weigh 300 kg. Give the magnitude and direction of the
(a) force on the floor by the crew and passengers,
(b) action of the rotor of the helicopter on the surrounding air,
(c) force on the helicopter due to the surrounding air.
Two objects A and B are thrown upward simultaneously with the same speed. The mass of A is greater than that of B. Suppose the air exerts a constant and equal force of resistance on the two bodies.
Suppose the ceiling in the previous problem is that of an elevator which is going up with an acceleration of 2.0 m/s2. Find the elongation.
Let m1 = 1 kg, m2 = 2 kg and m3 = 3 kg in the following figure. Find the accelerations of m1, m2 and m3. The string from the upper pulley to m1 is 20 cm when the system is released from rest. How long will it take before m1 strikes the pulley?
Find the acceleration of the block of mass M in the situation shown in the following figure. All the surfaces are frictionless and the pulleys and the string are light.
Find the acceleration of the 500 g block in the following figure.
A body of mass m moving with a velocity v is acted upon by a force. Write an expression for change in momentum in each of the following cases: (i) When v << c, (ii) When v → c and (iii) When v << c but m does not remain constant. Here, c is the speed of light.
In the previous problem (5.3), the magnitude of the momentum transferred during the hit is ______.
Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden?
