Physics 1121 Quiz 1 (Part 4)

Question 1

Electromagnetic force

Answer 1

This is a force that arises between electric charges or magnetic poles and may be attractive or repulsive.

Question 2

Nuclear

Answer 2

a force found in the nucleus of the atom, of which there are 2 types:

1)Strong – the force that holds atomic nuclei together.
This is the strongest of the 3 major forces.
2) Weak – a force associated with subatomic particles such as quarks.

Question 3

Gravity

Answer 3

a force of attraction between all objects that have mass. (Weakest of all primary forces)

Question 4

Newton’s Law of Universal Gravitation

Answer 4

It states that the amount of gravitational force depends on 2 factors:
1) mass of objects – directly proportional
2) distance between objects – inverse square relationship

Question 5

Newtons Equation

Answer 5

F = G m1 m2
d2

Question 6

Work

Answer 6

The result of a force moving an object a certain distance.
Work = force x distance

Question 7

Friction

Answer 7

A resistance to motion caused by two surfaces rubbing together. Extra energy must be expended to overcome the force of friction (Ff).

Question 8

Work to lift and object

Answer 8

Work to lift an object = mgh

Question 9

Circular motion

Answer 9

to maintain an object in circular motion, a balance between two different forces must be maintained

Question 10

Centripetal Force

Answer 10

a force that pulls inward toward the center of rotation. EX: ball on a string or satellite in orbit.
Fc = mv2

Question 11

Centrifugal force

Answer 11

a force pulling out away from the center of rotation and is the result of the object wanting to move in a straight line.

Question 12

Enegry

Answer 12

Ability to perform work

SI – Joule
CGS – erg
English – ft-lb

Question 13

Two common units to measure energy are:

Answer 13

Joule
b) Electron volt (eV) - the amount of energy an electron possesses while traveling across two oppositely charged electrical plates when a voltage of 1 volt is placed.
1 eV = 1.6 x 10-19 J.

Question 14

Types of energy

Answer 14

Mechanical = the actual or potential ability to perform work by virtue of motion.
There are two types of mechanical energy:
1) Kinetic = 1/2mv^2
2) Potential = mgh
G=9.8 m/s^2

Question 15

MKS and SI unit of heat

Answer 15

kilocalorie, which is the energy necessary to change the temperature of 1 kg of water by 1 degree Celsius.
1 kcal = 4186 J

Question 16

CGS unit of heat

Answer 16

calorie, which is the energy necessary to change the temperature of 1 gram of water by 1 degree Celsius.
1 cal = 4.186 J

Question 17

English unit of heat

Answer 17

British Thermal Unit (BTU), which is the energy necessary to change the temperature of 1 pound of water by 1 degree Fahrenheit.
1 BTU = 252 cal = 1054 J