Formula for potential energy is V=mgh, where m is mass in KG, g is earth acceleration (10 m/s^2), and h its height in meters. We know mass, acceleration is constant and also known, we know height also. Lets substitute
V=75*10*300=225000[J]=225[kJ] - its the answer
Answer:
Induced emf, 
Explanation:
The varying magnetic field with time t is given by according to equation as :

Where
are constant
Let
is the emf induced in the loop as a function of time. We know that the rate of change of magnetic flux is equal to the induced emf as:





So, the induced emf in the loop as a function of time is
. Hence, this is the required solution.
The object's speed will not change.
In fact, after the astronaut throws the object, no additional forces will act on it (since the object is in free space). According to Newton's second law:

where the first term is the resultant of the forces acting on the body, m is the mass of the object and a its acceleration, we see that if no forces act on the object, then the acceleration is zero. Therefore, the acceleration of the object is zero, and its velocity remains constant.
What's now called "Conventional current" is thought of as the flow of positive charge, from the battery's positive terminal to its negative one.
But it turns out that positive charges don't flow. The physical flow of charge is the flow of electrons. They come out of the battery's negative terminal, and carry negative charge around the circuit to the battery's positive one.
Gravity, friction, and air resistance are some examples.