3.2 Seatbelts & Newtons First Law

Question 1

Newton’s First Law (law of Inertia)

Part 1/3

Answer 1

1. Objects at rest stay at rest

Question 2

Newton’s First Law (law of Inertia)

Part 2/3

Answer 2

2. Objects in motion stay in motion

Question 3

Newton’s First Law (law of Inertia)

Part 3/3

Answer 3

3. Part I and 2 are only true when the net force, or total of all forces, on the object is zero.

Question 4

1st collision

Answer 4

‐ car strikes a pole
‐ pole exerts the force to stop the car

Question 5

2nd collision

Answer 5

‐ car stops, body keeps moving
‐ structures of car exert the force to stop the body

Question 6

3rd collision

Answer 6

‐ body stops, but the heart and brain keep moving
‐ body wall exerts the force to stop the heart or brain

Question 7

Pressure (Pa)

Answer 7

P = F/A

Question 8

Force (N)

Answer 8

F = P • A

Question 9

Area (m^2)

Answer 9

A = F/P

Question 10

Newton’s First Law

Answer 10

an object at rest stays at rest and an object in motion stays in motion in a straight line with constant speed unless acted upon by an unbalanced force

Question 11

net force

Answer 11

the combination of all forces acting on an object

Question 12

balanced forces

Answer 12

forces acting on an object that combine and form a net force of zero

Question 13

unbalanced forces

Answer 13

forces that produce a nonzero net force, which changes an object’s motion

Question 14

inertia

Answer 14

the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line; the tendency of an object to resist a change in its motion; depends on the mass

Question 15

force

Answer 15

an interaction between two objects that can result in an acceleration of either or both objects

Question 16

pressure

Answer 16

the amount of force exerted per unit area of a surface where the force is normal (perpendicular) to the surface

Question 17

area

Answer 17

the number of square units needed to cover a surface, calculated by multiplying length x width

Question 18

seatbelt

Answer 18

a device that holds passengers in their seats