Answer:
, repulsive
Explanation:
The magnitude of the electric force between two charged particles is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges of the two particles
r is the separation between the two charges
The force is:
- repulsive if the two charges have same sign
- Attractive if the two charges have opposite signs
In this problem, we have two electrons, so:
is the magnitude of the two electrons
is their separation
Substituting into the formula, we find the electric force between them:
And the force is repulsive, since the two electrons have same sign charge.
Answer:
43.7 °C
Explanation:
= Coefficient of linear expansion of brass = 
= Coefficient of linear expansion of steel = 
= Initial length of brass = 31 cm
= Initial length of steel = 11 m
= Total change in length = 3 mm
Total change in length would be
The final temperature is 43.7 °C
Answer:
Motion of a racing car on a circular track
Explanation:
Uniform circular motion means the motion of the object is in a circle with a CONSTANT SPEED.
The racing car will accelerate during its motion. Hence, it is not a uniform circular motion.
Answer:
C: You must know force and distance to calculate both.
Explanation:
A force is said to have done work, when it has succeeded in causing displacement in an object from its starting point.
Power can be defined as the rate of doing work.
The work can be calculated using the following formula:
Work done = Force × Displacement
The power can be calculated using the following formula:
Power = Work \ Time
In order to calculate the work and power, the force and distance should be known. The force and distance will help in the calculating the work, which will in turn help in the calculation of the power of the object.
Hence, the answer is you must know force and distance to calculate both.
