Mechanics

Question 1

Newton’s first law

Answer 1

an object in motion will remain in motion unless acted upon by an unbalanced force

Question 2

Newton’s second law

Answer 2

force=mass x acceleratoin

Question 3

Newton’s third law

Answer 3

when one object exerts a force on a second object, the second object exerts an equal force in the opposite direction of the first object

ex; a canon moving backwards after shotting a bomb

Question 4

Inertla

Answer 4

the tendency of an object to resist a change in motion

ex; a passenger will launch forward if a car suddenly stops suddenly

Question 5

What’s weight

Answer 5

the gravitational force experienced by an object

Question 6

Formula of weight

Answer 6

Fg=mg

g=(9.8)

Question 7

Whats apparent weight

Answer 7

the force exerted by the scale

Question 8

How does going up or down an elevator affect apparent weight

Answer 8

accelerating upwards:
feel heavier, scale reads less

accelerating downwards:
feel lighter, scale reads more

Question 9

what’s drag force

Answer 9

the force exerted by a fluid on an object opposing motion through a fluid

Question 10

what’s terminal velocity

Answer 10

the constant velocity that’s reached when the drag force equals the force of gravity Fg=Fd

Question 11

what’s normal force

Answer 11

the prepindicular contact force that a surface exerts on another surface

Question 12

what’s the resultant of two equivalent vectors in opposite directions

Answer 12

the resultant is zero

Question 13

Formula for resultant of two prepindicular vectors

Answer 13

R^2=A^2+B^2

Question 14

Formula for resultant of two prepindicular vectors with an angle between them

Answer 14

R^2=A^2+B^2-2ABcosthta

Question 15

what’s friction force and its two types

Answer 15

opposing force between two surfaces in contact
1.kinetic
2.static

Question 16

what’s Kinetic Fricition and its formula

Answer 16

Friction between moving surfaces:
Fk=microkxFn
microk=coofficient of kinetic force
Fn=normal force

Question 17

what’s static friction

Answer 17

friction between unmoving objects

Question 18

Characterstics of friction force

Answer 18

• does NOT depend on the surface area
• if thre is no force acting on the body, the static friction is zero
• there is neglible amounts of friction on smooth surfaces

Question 19

Why is static friction represented by an inequality? (<=)

Answer 19

Because it is not a fixed number, it can be a range of numbers up to a maximum point

Question 20

What’s the Fn normal force on an inclined plane

Answer 20

Fn=mgxcostheta

Question 21

what are x and y on an inclined plane

Answer 21

x = mg x cos theta
y = mg x sintheta

Question 22

does the mass affect the laws or calculations of free-fall?

Answer 22

no, because mass (m) does not play a role n any of the gravitational acceleration formulas

Question 23

what is the difference between the formulas for kinetic acceleration and gravitational acceleration?

Answer 23

we replace every (a) with (g) which equal 9.8m/s^2

Question 24

does a person’s mass change on the moon?

Answer 24

no, the mass of an object is conserved and constant.

the person’s weight is idfferent thoguh, because weight=mg

Question 25

What does the pulling force equal?

Answer 25

the weight of the object

weight=pulling force=mg