I think it’s Energy is lost when machines don’t work right.
Answer:

Explanation:
is the angle between the velocity and the magnetic field. So, the magnetic force on the proton is:

A charged particle describes a semicircle in a uniform magnetic field. Therefore, applying Newton's second law to uniform circular motion:

is the centripetal force and is defined as:

Here
is the proton's speed and
is the radius of the circular motion. Replacing this in (1) and solving for r:

Recall that 1 J is equal to
, so:

We can calculate
from the kinetic energy of the proton:

Finally, we calculate the radius of the proton path:

Initially, the spring stretches by 3 cm under a force of 15 N. From these data, we can find the value of the spring constant, given by Hook's law:

where F is the force applied, and

is the stretch of the spring with respect to its equilibrium position. Using the data, we find

Now a force of 30 N is applied to the same spring, with constant k=5.0 N/cm. Using again Hook's law, we can find the new stretch of the spring:
The bigger the object the greater the gravitational pull, so the farther away the big object is its gravitational force begins to decrease. Refer to the picture for more explanation.
Answer:
a positive test charge will move in the field
Explanation:
The direction of an electric field corresponds to the direction of motion of a positive test charge in the electric field. In fact:
- the electric field produced by a positive charge points outwards the charge --> this is because when a positive test charge is placed in this field, it will feel a repulsive force (because two positive charges repel each other), so it will move away from the positive charge that produces the field
- the electric field produced by a negative charge points towards the charge itself--> this is because when a positive test charge is placed in this field, it will feel an attractive force (because a positive and a negative charge attract each other), so it will move toward the negative charge that produces the field.