Answer:
K = 0.076 J
Explanation:
The height of the target, h = 0.860 m
The mass of the steel ball, m = 0.0120 kg
Distance moved, d = 1.50 m
We need to find the kinetic energy (in joules) of the target ball just after it is struck. Let t is the time taken by the ball to reach the ground.

Put all the values,

The velocity of the ball is :

The kinetic energy of the ball is :

So, the required kinetic energy is 0.076 J.
Answer:

Explanation:
The inital electrostatic force between the two spheres is given by:

where
is the initial force
k is the Coulomb's constant
q1 and q2 are the charges on the two spheres
r is the distance between the two spheres
The problem tells us that the two spheres are moved from a distance of r=20 cm to a distance of r'=10 cm. So we have

Therefore, the new electrostatic force will be

So the force has increased by a factor 4. By using
, we find

It woul be 0 because it is not moving. It is staying at a constant rate.
The first thing we need to do is figure out what equation to use. We will use the following kinematic equation...
Δx = (final velocity + initial velocity) x time / 2
We know that the car accelerates from rest, so initial velocity = 0 m/s
We also know final velocity = 20 m/s and time = 12s
Now we just need to plug everything in.
Δx = (20 x 12)/2 = 120 meters
Andaniol I’m for sure of it