Mechanics

Question 1

Def mechanics and its two parts

Answer 1

Mechanics is the study of the relationships among force, matter, and motion.
Kinematics deals with the description of motion
Dynamics deals with the causes of the motion.

Question 2

Velocity direction with that of an object

Answer 2

It points in the same direction as the object is moving.

Note: the magnitude of instantaneous velocity is the instantaneous speed.

Question 3

Speeding up and slowing down

Answer 3

• If velocity and acceleration point in the same direction, then the object is speeding up.
• If in opposite direction, it is slowing down.

Question 4

If an object is accelerating towards a point, then it must

be getting closer and closer to that point.

Answer 4

False; it’s not necessarily true. The direction of the acceleration is not necessarily the same as the direction of the velocity.

If we replace velocity in the statement below, it would be true.

Ex: it might be moving forward but slowing down in which the acceleration is negative, but is still moving forward before stoping.

Question 5

Kinematic equations for uniform acceleration

Answer 5

They are to be used when the acceleration is constant like in free-fall motion. If not, we can only use the calculus ways.

Question 6

Average speed & Av velocity

Answer 6

Rate of change of distance (total dist/change in time)

Rate of change of displacement