Mechanics Definitions

Question 1

Normal force,N

Answer 1

The force or the component of force which a surface exerts on an object with which it is in contact, and which is perpendicular to the surface

Question 2

Frictional force, f

Answer 2

The force that opposes the motion of an object and which acts parallel to the surface

Question 3

Static frictional force, fₛ

Answer 3

The force that opposes the tendency of motion of a stationary object relative to a surface

Question 4

Kinetic frictional force, fₖ

Answer 4

The force that opposes the motion of a moving object relative to a surface

Question 5

Newton’s First Law of Motion

Answer 5

A body will remain in its state of rest or motion at constant velocity unless a non-zero resultant/net force acts on it

Question 6

Newton’s Second Law of Motion

Answer 6

When a net force acts on an object, the object will accelerate in the direction of the force at an acceleration directly proportional to the force and inversely proportional to the mass of the object

Question 7

Newton’s Third Law of Motion

Answer 7

When object A exerts a force on object B, object B SIMULTANEOUSLY exerts an oppositely directed force of equal magnitude on object A

Question 8

Weight

Answer 8

The gravitational force the Earth exerts on any object on or near its surface

Question 9

Acceleration

Answer 9

Rate of change of velocity

Question 10

Free fall

Answer 10

As motion during which the only force acting on an object is the gravitational force

Question 11

Momentum

Answer 11

The product of an object’s mass and its velocity

Question 12

Newton’s Second Law of Motion in terms of momentum

Answer 12

The net (or resultant) force acting on an object is equal to the rate of change of momentum of the object in the direction of the net force.

Question 13

Impulse

Answer 13

The product of the resultant/net force acting on an object and the time the resultant/ net force acts on the object

Question 14

The Principle of Conservative of Linear Momentum

Answer 14

The total linear momentum of an isolated system remains constant (is conserved)

Question 15

Projectile

Answer 15

An object which has been given an initial velocity and then it moves under the influence of the gravitational force only

Question 16

.

Answer 16

Work done on an object by constant force F as F Δx cosθ, where F is the magnitude of the force, Δx the magnitude of the displacement and θ the angle between the force and the displacement

Question 17

Work-energy theorem

Answer 17

The work done on an object by a net force is equal to the change in the object’s kinetic energy

Question 18

Conservative force

Answer 18

A force for which the work done in moving an object between two points is independent of the path taken

Question 19

Non-conservative force

Answer 19

A force for which the work done in moving an object between two points depends on the path taken

Question 20

Power

Answer 20

The rate at which work is done or energy is expended