Physics 101
What is the value of pi you used in the lab?
3.14
If you have a circle with a radius of 1 cm, what is the area of that circle?
3.14 cm2
If you had a drum with an area of 50.24 meters2, what would the radius of that drum be?
4 meters
What would the total magnitude be (roughly) if Vector 1 had a magnitude of 20 and a degree of 45 in the N of E direction and Vector 2 had a magnitude of 25 and a degree of 30 in the N of E direction?
45
A 40-N block is supported by two ropes. One rope is horizontal, and the other makes an angle of 30 degrees with the ceiling. The tension in the rope attached to the ceiling is approximately
80 N
What is roughly the weight of 1m³ of air at standard pressure and temperature?
9.8 N
The weight of a 10-kg block is
98 N
What famous equation is Newton's Second Law of Motion?
F = ma
A moving body cannot be in equilibrium.
False
According to convention, negative work means that the direction of the work is downward or to the left.
False
If an object's velocity is decreasing constantly, it will always have a negative acceleration.
False
If we consider friction, the potential energy at the top of an inclined plane is less than it would be in the absence of friction.
False
Newton's second law of motion is strictly true only in the absence of friction forces.
False
Only vectors having the same dimensions may be added.
False
The kilogram is the metric unit of weight.
False
The motion of a projectile fired at an angle is an example of uniformly accelerated motion.
False
The range of a projectile depends only on its initial speed.
False
The weight of a 9.8-kg body is 1 N.
False
Vector addition can be performed only for concurrent vectors.
False
When a projectile is fired at a 45 degree angle, its maximum height will equal its range.
False
When you add Vector 1 and Vector 2, how do you do it?
You add the x-component of Vector 1 to the x-component of Vector 2. Then add the y- component of Vector 1 to the y-component of Vector 2.
To apply the second condition for equilibrium, the axis of rotation
may be chosen anywhere
A 60-lb block rests on a smooth horizontal surface. The horizontal force that just starts the block moving is found to be 30 lb. Which of the following is true for this situation?
μs = 0.5
What is density?
ρ = m/v
What are the units of area you used in your lab?
(meters)2
What is the density of water?
1 g/cm³
Suppose you are in a car traveling 3 m/s in town. You reach the outskirts of town where the speed limit is 5 m/s. Naturally, you accelerate to get to the new speed limit and it takes you 2 seconds to reach it. What was your acceleration?
1 m/s²
If two vertical ropes are used to support a 20-N weight, the tension in each rope must be
10 N
What is acceleration?
The rate of change of velocity over time.
What is the x - component of a vector (roughly) that has a magnitude of 1.414 and a degree of 45 in the N of E direction?
1
A girl and a boy carry a sack weighing 40 N on a pole between them. If the pole is 6 m long and the load is 2 m from the girl, what force does the boy exert?
13.3 N
If μk = 0.1, the force required to push a 20-N sled up a 40 degree incline with constant speed is approximately
14.4 N
In Data Table 2, you were given different radii. What was the maximum significant figures that the data displayed?
4
Suppose a vector has an x-component of 3 and a y-component of 4. What would the magnitude of the vector be?
5
A 1-hp motor will lift a 200-lb block to what height in 2 s?
5.5 ft
If a race track had a circumference of 0.250 miles, what would be the area of the circle the race track creates?
About 0.005 miles2
What is Bernoulli's Law?
All of the above.
What is free fall?
All of the above.
Why is equilibrium important?
All of the above.
Why is it important to have your car breaks checked and to slow down ahead of your stop?
All of the above.
What is Poiseuille's Law?
An equation that describes the pressure drop of a viscous fluid.
What is gravity?
Answers 1 and 2
A 40-N block slides down a board with constant speed when the angle of elevation is 30 degrees. Which of the following is not true for this situation?
Fk = 34.6 N
In physics, what is equilibrium?
The state of a body at rest or in uniform motion in which the resultant of all forces on it is zero.
Suppose you are riding in a car heading to the right. You see a red light approaching and decided to slow down. When you are slowing down, your acceleration is in what direction?
To the left.
Action and reaction forces do not neutralize each other because they act on different objects.
True
If an apple drops from a tree at the same instant a projectile is fired toward it from the ground, they will still collide in the air.
True
In applying the second condition for equilibrium, the axis of rotation may be chosen for convenience.
True
Newton's second law of motion applies either to a system of bodies moved together as a whole or to any body that is a part of such a system.
True
If sin(θ) = opposite/hypotenuse and cos(θ) = adjacent/hypotenuse, what is tan(θ)?
opposite/adjacent
An arrow is shot vertically upward with an initial velocity of 96 ft/s. It will first come to a stop in
3 s
A car accelerates from rest at 4 m/s^2. How far will it travel in 4 s?
32 m
Suppose you had the following: Vector 1 = magnitude of 45 and degree of 26 in the N of E direction Vector 2 = magnitude of 75 and degree of 40 in the S of W direction What would the total magnitude and direction be if you add Vector 1 and 2 together?
33.2 in the S of W direction
A force of 16 N is directed 30 degrees north of east. The y component of the force is
8 N
What is Kepler's Second Law of Planetary Motion?
A line from the Sun to any planets sweeps out equal areas in equal time.
What is Archimedes Principle?
A principle that states any floating object displaces its own weight of fluid.
In physics, what is a vector?
A quantity that has a magnitude and a direction.
In physics, what is torque?
A rotational or twisting effect of a force causes on an object.
Which of the following cannot apply for a body in translational equilibrium?
Constant speed
What did the line of your Graph #1 resemble?
Diagonal and straight line
What is the formula for fluid pressure?
P = ρgh
What theorem is used to find hypotenuse of a triangle when given the other two sides?
Pythagorean
What is Kepler's Third Law of Planetary Motion?
P² = a³
In physics, what is weight?
The force on an object with mass due to gravity.
What is Kepler's First Law of Planetary Motion?
The planets move in elliptical orbits with the Sun at one focus.
What is center of gravity?
The point in a system where the mass of the entire system is considered to be concentrated.
What is specific gravity?
The ratio of the density of a material to the density of water at 4 degrees Celsius.
The British unit for mass is the slug.
True
The difference between two vectors is obtained by adding one vector to the negative of the other.
True
A 60-lb boy sits on the left end of a 12-ft seesaw, and a 40-lb boy sits on the right end. The resultant torque about the center is approximately
+120 lb á ft
A rope is wrapped in a clockwise direction around a 12-in.-diameter axle. If a force of 20 lb is exerted on the rope, what is the resultant torque?
-10 lb á ft
A 30-kg girl steps to shore from a 60-kg boat, giving the boat an acceleration of 2 m/s^2. If water resistance is neglected, the girl receives an acceleration of
-4 m/s^2
A 200-lb block is at rest on a 37 degree inclined plane. The normal force exerted by the plane is approximately
160 lb
In what year did Kepler inherit a large amount of data to help him discover his three laws?
1601
Suppose you had the following: Vector 1 = magnitude of 30 and degree of 17 in the N of W direction Vector 2 = magnitude of 15 and degree of 45 in the S of E direction What would the total magnitude and direction be if you add Vector 1 and 2 together?
18.2 in the S of W direction
Suppose you have a drum that has a 6 meter diameter. What would the circumference and area be?
18.84 meters circumference and 28.26 meters2 in area
A rope is wrapped around a 16-in.-diameter drum in a counterclockwise direction. What force must be exerted on the rope to give a torque of 120 lb ft?
180 lb
Suppose a vector had an x- component of 1.73 and a y-component of 1. What would the angle of the vector be if it is in the N of E direction?
30
A 20-lb force acts to the left while an 80-lb force acts upward and to the right at an angle of 37 degrees. The magnitude of the resultant force is
65 lb
Which of the following is not necessary for work to be done?
A constant speed
What is Buoyant force?
A force exerted by a fluid, that opposes an object's weight.
Which is a vector quantity?
Displacement
In Procedure 3, you steadily increased the diameter of your circle. What happens to the circumference of that circle?
It increases
Which is a scalar quantity?
Speed
What is the difference between speed and velocity?
Speed is the magnitude of velocity. Velocity is a vector.
What is a circumference?
The distance around the edge of an object.
What is terminal velocity?
The fastest velocity an object can achieve when in free fall.
The kilogram is equivalent to a mass of 1000 g.
True
The kilowatthour is a unit of energy.
True
The mass of a body is dependent on the acceleration due to gravity.
True
The maximum force of static friction is directly proportional to the weight of a body.
True
The net torque will be the same if a force is doubled but moved to a point halfway to the axis of rotation.
True
The parallel force required to move an object over a surface at constant speed is equal to the magnitude of the force of kinetic friction.
True
The velocity and position of a free-falling body after 2 s are numerically the same.
True
The weight of a body whose mass is 1 slug is equal to approximately 32 lb.
True
When considering only concurrent forces, we do not need to calculate torques.
True
Kepler was an apprentice to what famous astronomer?
Tycho Brahe
When a 1-N force acts on a 1-kg body, the body receives
an acceleration of 1 m/s^2
To compute torque, one must know
both of these
The algebraic sign of acceleration depends on
the direction on the force of the accelerated object
