Answer:
a) Time = 2.67 s
b) Height = 35.0 m
Explanation:
a) The time of flight can be found using the following equation:
(1)
Where:
: is the final position in the horizontal direction = 80 m
: is the initial position in the horizontal direction = 0
: is the initial velocity in the horizontal direction = 30 m/s
a: is the acceleration in the horizontal direction = 0 (the stone is only accelerated by gravity)
t: is the time =?
By entering the above values into equation (1) and solving for "t", we can find the time of flight of the stone:

b) The height of the hill is given by:
Where:
: is the final position in the vertical direction = 0
: is the initial position in the vertical direction =?
: is the initial velocity in the vertical direction =0 (the stone is thrown horizontally)
g: is the acceleration due to gravity = 9.81 m/s²
Hence, the height of the hill is:
I hope it helps you!
Answer:
The force per unit length is 
Explanation:
The current carrying by each wires = 2.85 A
The current in both wires flows in same direction.
The gap between the wires = 6.10 cm
Now we will use the below expression for the force per unit length. Moreover, before using the below formula we have to change the unit centimetre into meter. So, we just divide the centimetre with 100.

Answer:
Mass can never be negative. Everything has mass. Just like how they ask you to find area under the graph in maths. If the area is in the 3rd and 4th quadrant, when calculated, you would get negative answer.However, area can not be negative because it is a place/ location. It's exactly the same as mass.
Opposite force in the opposite.
Answer:
The current is not used up. The electrons flow through the entire circuit and this travel is the current. They flow until they are not charged anymore. That is also why the circuit must be closed or else electrons would escape not just light it up for a second then go out.
Explanation: