Answer:
The final speed of puck 1 is 0.739 m/s towards west and puck 2 is 2.02 m/s towards east .
Explanation:
Let us consider east as positive direction and west as negative direction .
Given
mass of puck 1 , 
mass of puck 2 , 
initial speed of puck 1 , 
initial speed of puck 2 , 
Final speed of puck 1 and puck 2 be 
respectively
Apply conservation of linear momentum
=>
=>
-----(A)
Since collision is perfectly elastic , coefficient restitution e=1
=>
------(B)
From equation (A) and (B)
and 
Thus the final speed of puck 1 is 0.739 m/s towards west and puck 2 is 2.02 m/s towards east .
Down stream it would be going 20 mph and up stream 10 mph
The mass of the bird is 0.32 kg.
<u>Explanation:</u>
Gravitational potential energy, the energy exhibited by an object at rest due to the influence of gravitational force. So the increase in distance of object from the surface of earth leads to increase in the gravitational potential energy. Thus,
So, as the gravitational potential energy is given as 2033 J and the position of bird placed on the tall tower is 639 m away from the bottom, then the mass (m) of the bird can be found as below.
So, finally we get the bird's mass as,
m of bird = 0.32 kg
