Answer:

Explanation:
Assuming that cars 4 and 5 have same mass so that the momentum
P=mv where m is mass and v is velocity hence
Momentum=0+2mv+3mv=5mv
The final mass is 2m+3m=5m
From aw of conservation of momentum
hence 
Therefore, the speed is 
1575 N
Explanation:
Step 1:
Let us consider that 350 J of energy is spent by that person to push a couch to 4.5 m from its initial position.
Let F be the force required and E be the energy spent and D be the distance traveled by the couch from its initial state.
In Physics, Work done = Force / Displaced distance
Step 2:
Let the work done be 350 J and Distance be 4.5 m
Then Force exerted = 
The atomic procedure clarifies why this is the situation is beginning from carbon ( the nuclear number is 6), the most widely recognized atomic responses include the combination of an extra helium core. I hope the answer will help you.
Answer:
the answer for the question is C
Weight equals mass multiplied by the acceleration due to gravity.