Answer:
60 Ohms
Explanation:
Ohms law states that the voltage in the circuit is directly proportional to the current through the circuit components and expressed as
V=IR
Where V is the voltage, I is current and R is resistance
Making R the subject of the formula then

Substituting 3.0V for V and 0.05 A for I then

Therefore, resistance is 60.0 Ohms
D is the correct answer, assuming that this is the special case of classical kinematics at constant acceleration. You can use the equation V = Vo + at, where Vo is the initial velocity, V is the final velocity, and t is the time elapsed. In D, all three of these values are given, so you simply solve for a, the acceleration.
A and C are clearly incorrect, as mass and force (in terms of projectile motion) have no effect on an object's motion. B is incorrect because it is not useful to know the position or distance traveled, unless it will help you find displacement. Even then, you would not have enough information to use a kinematics equation to find a.
For an uniformly accelerated motion, we can write

where

is the acceleration of this motion, which in this problem is the gravitational acceleration, with a negative sign because it points downward, against the direction of the motion; h=0.540 m is the distance covered by the flea, and

is the initial velocity.
At the maximum height, the velocity is zero, so

. Therefore we can solve to find

:
Answer:
The strength of the magnetic field decreases as a result of removing one of those batteries.
Hope this helps!