Download Physics Chapter 1-3 Review

Physics Chapter 4-6 Review
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Terminology
Force
A measure of an object’s mass (inertia) times its acceleration.
Measured in Newtons (kg·m/s2)
Inertia
The reluctance of any object to change its state of motion.
Mass is the measure of inertia
Weight
Weight: the force of gravity on an object.
Mass and weight are proportional not equal. Objects with
great mass have great weight
Pressure is the amount of force per unit area.
Pressure
Friction
A force that acts between materials that touch as they move
past each other.
Equilibrium
Net forces equal zero. Forces are balanced
(object’s motion will be unchanged)
The point at which an object in free fall stops accelerating.
Terminal velocity
Air resistance
The friction acting upon an object moving through the air is
called air resistance.
The sum of all forces acting on an object
Net forces
Tension
Force on a string rope or cable due to and object attached to
it. Based on that object mass time its gravitational
acceleration.
Problems:
1. What is the mathematical relationship between acceleration and force?
Directly proportional - Linear
2. What is the relationship between acceleration and mass?
Inversely proportional - Linear
3. Which of Newton’s law look at these relationships?
Newton’s 2nd Law F=ma
4. Observe the two diagrams below. In the first diagram A, the angles in which the
cables are set are equal. Would the combined tension in the cables be greater or
lesser than the weight of the light? What happens to the tension as you move the
cables further apart? In the second diagram B, which cable has the greater tension?
A
B
5. Draw a free body diagram for the picture below. Label all the forces acting on it.
What is the net force on the mass if A) the mass is at rest, B) the mass is sliding
down at constant velocity and C) the mass is accelerating down the ramp?
A) ΣF = 0
B) ΣF = 0
C) ΣF ≠ 0
6. Give the reaction for the following action forces:
a. A car hits a brick wall : The Brick wall hits the car
b. Gravity pulls a boulder to earth : Gravity pulls the earth to the boulder
c. An ice skater pushes off the rail : The rail pushes against the ice skater
7. What would the acceleration be for a cyclist with a total mass of 100 kg (including
bike) providing a 50 N forward force on the road while the road created a 10 N
frictional force on the cyclist?
a = ΣF /m = 50 N – 10 N / 100 kg = 0.4 m/s2
8. Calculate the force of a 60 kg person experiencing a 9 g force on a roller coaster ride.
ΣF = ma = (60 kg)(9 g)(10 m/s2) = 5,400 N_