Answer:
wrong statement : Momentum is not conserved for a system of objects in a head-on collision.
Explanation:
In a head on collision of two objects , two equal and opposite forces are created at the point of collision . These two forces create two impulses in opposite direction which results in equal and opposite changes in momentum in each of them . Hence net change in momentum is zero. In this way momentum is conserved in head on collision of two objects.
Answer:
The coupled velocity of both the blocks is 1.92 m/s.
Explanation:
Given that,
Mass of block A, 
Initial speed of block A, 
Mass of block B, 
Initial speed of block B, 
It is mentioned that if the two blocks couple together after collision. We need to find the common velocity immediately after collision. We know that due to coupling, it becomes the case of inelastic collision. Using the conservation of linear momentum. Let V is the coupled velocity of both the blocks. So,

So, the coupled velocity of both the blocks is 1.92 m/s. Hence, this is the required solution.
Hear is transferred from the heating elements to the Pot by Conductivity
Explanation:
When Joe works alone, the total number of words he typed can be given by:
Total words = (40 words per minute) x (60 minutes per hour) x (2.5 hours)
Total words = 6000 words
Now, when Joe and Mark work together, let 'y' be the number of hours for which they both work simultaneously:
Total words = Words Typed by Joe + Words Typed by Mark
6000 = {(40 words per minute) x (60 minutes per hours) x (y hours)} + {(20 words per minute) x (60 minutes per hours) x (y hours)}
6000 = 2400y + 1200y = 3600y
y = 1.67 hours = 1 hour and 40 minutes
Thus, working together simultaneously, Joe and Mark will take 1 hour and 40 minutes to complete the report.