Dynamics - Semester One

Question 1

What is Einstein’s first postulate?

Answer 1

The laws of physics are the same in every inertial frame of reference.

Question 2

What is Einstein’s second postulate?

Answer 2

The speed of light in a vacuum is the same in all inertial frames of reference and is independent of the motion of the surface.

Question 3

What is Newton’s first law of motion?

Answer 3

A body acted on by no net force moves with constant velocity (which may be zero) and zero acceleration.

Question 4

What is Newton’s second law of motion?

Answer 4

If a net external force acts on a body, the body accelerates. The direction is the same as the net force.

F = m a

Question 5

What is Newton’s third law of motion?

Answer 5

If Body A exerts a force on Body B (an “action”) then body B exerts a force on Body A (a “reaction”.)Fab = - Fba

Question 6

Friction force F_k =

and for static friction….

Answer 6

F_{k =} μ_k n

F_s <= μ_s n

Question 7

For frictional force n =

Answer 7

n = normal force

Bassically force extered by surface onto the object….

Question 8

Acceleration of an object under unifrom circular motion

a =

Answer 8

a = ω² R

r = radius

ω = 2π /T

Question 9

Work energy thereom W_total =

Answer 9

W_total ​= K₂ - K₁

Question 10

Force from preasure F =

Answer 10

F = p A

(A = surface area)

Question 11

What is the frictional force called when the object is not moving?

Answer 11

Static friction

Question 12

Work done on a body W =

Answer 12

W = F s