Forces

Question 1

Define force

Answer 1

A force is a push or pull that can cause an object to change its motion, speed up, slow down, or remain stationary.

Question 2

Define dynamics

Answer 2

Dynamics is the study of the causes of motion (forces).

Question 3

Define system diagram

Answer 3

A system diagram is a simple sketch of all the objects involved in a situation.

Question 4

Define free body diagram

Answer 4

A free body diagram is a simple drawing of an object showing all the forces acting on it.

Question 5

Define applied force (Fapp)

Answer 5

A force that results when one object makes contact with another and pushes or pulls it.

Question 6

Define tension (Ft)

Answer 6

A pulling force from a rope or string.

Question 7

Define friction (Ff)

Answer 7

A motion which opposes the sliding of two surfaces across one another; friction acts opposite motion or attempted motion.

Question 8

Define normal force (Fn)

Answer 8

A perpendicular force exerted by a surface on an object in contact with the surface.

Question 9

Define force of gravity

Answer 9

A force of attraction between any 2 objects due to mass.

Question 10

What are non-contact forces also called?

Answer 10

Action at a distance forces

Question 11

What is Newton’s first law?

Answer 11

Newton’s first law states that if the net external force on an object is zero, the object will remain at rest or continue to move at a constant velocity.

Question 12

Define inertia

Answer 12

Inertia is the property of matter that causes an object to resist changes in motion.

Question 13

How are inertia and mass related?

Answer 13

Inertia is directly proportional to the mass of an object.

Question 14

What is Newton’s second law?

Answer 14

Newton’s second law states that if the net external force on an object is not zero, the object will accelerate in the direction of this net force.

Question 15

How are acceleration and the net force related?

Answer 15

The object’s acceleration is directly proportional to the an object’s net force.

Question 16

How is an object’s acceleration and mass related?

Answer 16

The object’s acceleration is inversely proportional to an object’s mass.

Question 17

What is Newton’s third law?

Answer 17

Newton’s third law states that for every force, there is a simultaneous reaction force that is equal in magnitude but opposite in direction.

Question 18

What are the action/reaction force properties?

Answer 18

The action/reaction forces happen at the same time but act on different objects.

Question 19

When an object is tied together by a rope/string, it is experience the same __________.

Answer 19

Acceleration

Question 20

What direction does air resistance act in?

Answer 20

Air resistance acts in the opposite direction of the velocity of an object.

Question 21

Define terminal speed

Answer 21

Terminal speed is the maximum constant speed of a falling object.

Question 22

Define mass

Answer 22

Mass is the quantity of matter in an object.

Question 23

Define weight

Answer 23

Weight is a measure of the force of gravity acting on an object.

Question 24

How can you change mass?

Answer 24

The only way to change mass is to add or remove matter.

Question 25

How can you lose weight?

Answer 25

The only way you can lose weight is the escape Earth’s gravitational field of 9.8 m/s squared that is acting on an object on Earth at all times.

Question 26

Define static friction (Fs)

Answer 26

Static friction is a force that prevents a stationary object from starting to move.

Question 27

Define kinetic friction (Fk)

Answer 27

Kinetic friction is a force that opposes the motion of a moving object. It is caused by the surfaces in contact with one another.

Question 28

What is harder to move: static friction or kinetic friction?

Answer 28

Static friction is harder to move because the applied force must over the static friction’s max threshold in order for the object to start moving.

Question 29

What are the 2 factors that affect friction?

Answer 29

The types of surfaces and the normal force acting on an object.

Question 30

Define coefficient of friction

Answer 30

The coefficient of friction is the ratio of the force of friction acting on an object to the normal force.

Question 31

What happens when a car hydroplanes?

Answer 31

When a car hydroplanes, it means it is not touching the surface therefore it has no friction acting on it. A standard car has treads 7-8 mm deep to allow water/snow to squeeze through the tire and maintain the tire’s contact with the road. If the treads start to wear out less water gets in thus allowing for the tire to start moving on water. This is dangerous because there is no friction acting on the car.

Question 32

What are some characteristics of an artificial hip?

Answer 32

An artificial hip must be able to function properly because it needs to support the whole upper body. For this, the materials need to be flexible yet sturdy, resistant and durable. It must be able to work for a long time and resist wearing down.