Your answer is C) <span> the potential energy of an object is always greater than its kinetic energy </span>
To calculate the force of impact F, first lets calculate the acceleration a of the ball:
a=v/t where v is the velocity of the ball and t is time
a=32/0.8=40 m/s²
To get the force F we need the Newtons second law:
F=m*a where m is the mass of the ball and a is the acceleration.
F=m*a= 0.2*40 = 8 N
So the impact force is F= 8 N.
Answer: C.
Explanation:
For a parallel-plate capacitor where the distance between the plates is d.
The capacitance is:
C = e*A/d
You can see that the distance is in the denominator, then if we double the distance, the capacitance halves.
Now, the stored energy can be written as:
E = (1/2)*Q^2/C
Now you can see that in this case, the capacitance is in the denominator, then we can rewrite this as:
E = (1/2)*Q^2*d/(e*A)
e is a constant, A is the area of the plates, that is also constant, and Q is the charge, that can not change because the capacitor is disconnected.
Then we can define:
K = (1/2)*Q^2/(e*A)
And now we can write the energy as:
E = K*d
Then the energy is proportional to the distance between the plates, this means that if we double the distance, we also double the energy.
The gravitational force between two objects is given by
where
G is the gravitational constant
m1 and m2 are the masses of the two objects
r is the separation between the two objects
In this problem,
,
and
, therefore the gravitational force between the two objects is
