Answer:

Explanation:
Since our equation is
and F=781.25 N when t=1.49s, we have:

The impulse of a force is
, so for our case we have:

For our case
and
, so we have:

Answer:
The new intensity decreases by a factor of 16.
Explanation:
The intensity of sound wave is given by :

P is power
A is area

or
, r is distance from the source
If the distance from the source is increased by a factor of 4, r' = 4r
So,

So, the new intensity decreases by a factor of 16.
No, they are not both correct. Mai is correct. Water is a solution
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 
Answer:
456
Explanation:
impulse = Force x (time of contact)
this isn't really much information but hope this helps !: )