4. A trolley of mass 2kg rests next to a trolley of mass 3 kg on a flat bench as shown in the diagram. When the spring is released
between the trolley's, they pushed apart. The 2kg travels to left at a
velocity of 6m/s.
a. What is the total momentum of the trolleys before
separation?
b. What is the total momentum of the trolleys after
separation?
c. What is the momentum of of 2kg trolley after
separation
d. What is the momentum of 3kg trolley after separation?
e. What is the velocity of the 3kg trolley?

a-The total momentum of the trolleys before separation=0

b.The total momentum of the trolleys after  separation=0

c. The momentum of 2kg trolley after  separation=12kg-m/sec

d. The momentum of 3kg trolley after separation=-12kg-m/sec

e. The velocity of the 3kg trolley=4kg-m/sec

Given-

Trolley A with mass= 2kg

Trolly B with mass= 3kg

Velocity of trolly A =6m/sec

A- Total momentum of the trolleys before separation-

Here, in this problem both the trolleys are in the rest position hence the momentum of both trolleys = 0

B- Total momentum of the trolleys after  separation-

We know that motion never changes in an isolated collection of objects,

hence the momentum of the trolleys before and after the separation=0

C- Momentum of the Trolley A (2kg)-

It is known that momentum= Mass x Velocity

Hence, the momentum of the 2kg trolley is 12 kg-m/sec

D- Momentum of the Trolley B (3kg)-

As we know that  motion never changes in an isolated collection of an object hence the total moment of after saparation = 0

hance the momentum of the trolley B will be equal and opposite to the momentum of trolley A=

Momentum of trolley B (3kg) is -12kg-m/sec

E- The velocity of the 3kg trolley-

The momentum of trolley A= Momentum of trolley B

The value of the velocity of the 3kg trolley is -4m/sec

For more about the momentum, follow the link below-

link

a. The total momentum of the trolleys which are at rest before the separation is zero

b. The total momentum of the trolleys after separation is zero

c. The momentum of the 2 kg trolley after separation is 12 kg·m/s

d. The momentum of the 3 kg trolley is -12 kg·m/s

e. The velocity of the 3 kg trolley = -4 m/s

Explanation:

a. The total momentum of the trolleys which are at rest before the separation is zero

b. By the principle of the conservation of linear momentum, the total momentum of the trolleys after separation = The total momentum of the trolleys before separation = 0

c. The momentum of the 2 kg trolley after separation = Mass × Velocity = 2 kg × 6 m/s = 12 kg·m/s

d. Given that the total momentum of the trolleys after separation is zero, the momentum of the 3 kg trolley is equal and opposite to the momentum of the 2 kg trolley = -12 kg·m/s

e. The momentum of the 3 kg trolley = Mass of the 3 kg Trolley × Velocity of the 3 kg trolley

∴ The momentum of the 3 kg trolley = 3 kg × Velocity of the 3 kg trolley = -12 kg·m/s

The velocity of the 3 kg trolley = -12 kg·m/s/(3 kg) = -4 m/s

d. air pressure decreases as altitude increases.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.