Question

a rocket engine is mounted wagon which is free to move horizontally . when the first engine is ignite , the wagon acquires some acceleration. this acceleration is independent of
options
acceleration of gravity, mass of exhausted gases, mass of wagon, velocity of exhausted gases . please give the correct option..

Answer 1

Answer:

I think acceleration of gravity is correct

Answer 2

Answer:

Explanation:

potential energy of pendulum is converted to kinetic energy of pendulum and kinetic energy of wagon.

assuming final velocity at mean position is v

1

​

 for pendulum and  v

2

​

 for wagon,

so balancing the energy,

mg(l−lcos60)=

2

1

​

mv

1

2

​

+

2

1

​

mv

2

2

​

also no external force is acting on the system in x direction so moment will be balanced in x direction.

mv

1

​

=mv

2

​

 =>v

1

​

=v

2

​

=v

we get from both the above equations

2.

2

1

​

mv

2

=mgl

2

1

​

v=

2

gl

​

​

so answer is v=

2

gl

​

.