Answer:
All of the above
Explanation:
The magnitude of the magnetic force on a current-carrying wire held in a magnetic is given by the equation 
Where B = Strength of the magnetic field
I = The current carried by the wire
l = length of the wire in the magnetic field
θ = Angle between the wire and the magnetic field
Based on the relationship written above, the magnitude of the magnetic force on the current - carrying wire in the magnetic field depends on the strength of the magnetic field (B), length of the wire(l), current in the wire (I).
All the options are correct.
There are only two things you can do to increase the work output of a machine:
1). Increase the work INput to the machine.
2). Make the machine more efficient ... do things like lubricating it better to eliminate some internal friction.
Explanation:
First, simplify the circuit. Then calculate the parallel and consecutive resistances to find the answer.
Answer:
A. True
Explanation:
When a stone is thrown straight-up, it has an initial velocity which decreases gradually as the stone move to maximum height due to constant acceleration due to gravity acting downward on the stone, at the maximum height the final velocity of the stone is zero. As the stone descends the velocity starts to increase and becomes maximum before it hits the ground.
Height of the motion is given by;

g is acceleration due to gravity which is constant
H is height traveled
u is the speed of throw, which determines the value of height traveled.
Therefore, when the stone is caught at the same height from which it was thrown in the absence of air resistance, the speed of the stone when thrown will be equal to the speed when caught.
The periodic sign of magnesium is ------> mg