Answer:
screw and pulley
Explanation:
because they didn't have any of the other tools in that time
To calculate the change in kinetic energy, you must know the force as a function of position. The work done by the force causes the kinetic energy change
Explanation:
The work-energy theorem states that the change in kinetic enegy of an object is equal to the work done on the object:

where the work done is the integral of the force over the position of the object:

As we see from the formula, the magnitude of the force F(x) can be dependent from the position of the object, therefore in order to solve correctly the integral and find the work done on the object, it is required to know the behaviour of the force as a function of the position, x.
Answer:
Induced current, I = 18.88 A
Explanation:
It is given that,
Number of turns, N = 78
Radius of the circular coil, r = 34 cm = 0.34 m
Magnetic field changes from 2.4 T to 0.4 T in 2 s.
Resistance of the coil, R = 1.5 ohms
We need to find the magnitude of the induced current in the coil. The induced emf is given by :

Where
is the rate of change of magnetic flux,
And 



Using Ohm's law, 
Induced current, 

I = 18.88 A
So, the magnitude of the induced current in the coil is 18.88 A. Hence, this is the required solution.
Answer:
is this a physics questions???
and i didnt get u btw