PHYS 1030 Ch. 4
How is circular motion different than rotary motion?
Circular motion involves a small object (that can be considered a point) circling a center. It only has one linear speed. Rotary motion is a solid object, with each part having a different linear speed.
In horizontal projectile motion free from friction but not free of gravity,
the horizontal velocity is constant and the vertical acceleration is constant.
In circular motion, the acceleration is ____ if you have a constant speed going around the circle.
toward the center
In circular motion, the force is ____ if you have a constant speed going around the circle
toward the center
Circular motion is caused by a force that points _______________,
toward the center of the circle
In projectile motion, the ___ component uses 9.80 m/s2.
vertical
The resultant of two vectors that are in non-parallel directions (at an angle) can be solved by
solving graphically (draw to scale)
A car going around a curve hits a slick spot. What will be the direction of the slide?
straight ahead
The resultant of two vectors that are in opposite directions can be solved by
subtraction
A coach swings a baseball on the end of a 2.0-m long, stout string for his teeny players to practice batting. The ball has a mass of 250 g and a speed of 12 m/s. What isthe acceleration of the ball?
72 m/s2
A centripetal force acts
perpendicular to the velocity and toward the center ofthe path
A racecar driver has to hold on tightly when going around a banked curve. How many "gs" does the driver experience in a 2200 kg car going around a circle with a radius of 95 meters at 25 m/s?
0.67g
Add graphically 20 km right plus 10 km left
10km right
A 600.0 kg roller coaster is going around vertical loop with a radius of 10.0 meters. The speed of the coaster is 14m/s at the top of the loop. What it the magnitude of the CENTRIPETAL force on the roller coaster, to the nearest whole number of newtons?
11,760
A 2400 kg truck is going around a curve with a radius of 80 meters. The speed of the truck is a constant 21 m/s/ What it the force on the truck, to the nearest whole number of newtons?
13230
A bomb is dropped from an airplane at a height of 1200 meters. How long will it take to hit the ground?
15.6s
A racecar driver has to hold on tightly when going around a banked curve. Approximately what is the centripetal force on a 2,490.0 kg car going around a circle with a diameter of 190.0 meters at 25.0 m/s?
16,382
A golf club head can be thought of as undergoing circular motion when you swing the club. If the club head has a mass of 0.65 kg, a speed of 24 m/s and a radius of 2.2 meters, (club length + arm length) what is the force on the club head due to the swing?
170N
The tension in the stout string of the previous problem willbe
18N
Add graphically A scout walks 4 miles north, then 2 miles east and then 3 miles south. What is the resultant?
2.2 miles at 27 degrees North of East
A baseball player throws a ball horizontally at 30 m/s from a height of 2.1 meters. About how far horizontally will it fly in metes before it hits the ground.
20
What is the horizontal component of a 250 m/s vector at 33 degrees above the horizon?
210 m/s
Add graphically 20 km east plus 10 km north
22 km at 27 degrees North of East
A projectile is launched horizontally from a height of 2.2 meters at 34 m/s. How far will it travel horizontally before it hits the ground?
23
A bomb is dropped from an airplane at a height of 1200 meters. The plane is flying horizontally at 160 m/s. About how far horizontally will the bomb fly before it hits the ground?
2500m
A baseball is thrown horizontally from a height of 6 meters at a speed of 24 m/s. How far will it travel horizontally before it hits the ground?
26.6
Add graphically 20 km east plus 10 km northeast
28 km at 15 degrees North of East
Add graphically 20 km east plus 10 km east
30km E
Solve graphically A 640 N force on a diagonal roof stud pushes down at an angle of 60° to the horizontal. What are the horizontal and vertical components of the force?
320 N horizontal 545 N vertical
A forensic scientist (CSI) is trying to find a weapon thrown off a bridge into the lake. Assume it is thrown horizontally and it sinks straight down once it hits the water. The bridge height is 15 meters and a normal throwing speed is 22 m/s. How far from the bridge should you search?
39
A 600 kg roller coaster is going around vertical loop with a radius of 10 meters. The speed of the roller coaster is 13 m/s at the top of the loop. This is a third part of a 3 part question. The velocity is different, but use the same formulas from the previous 2 questions. What it the magnitude of the NORMAL force on the roller coaster, to the nearest whole number of newtons?
4260
What angle of launch will give a projectile the maximum distance along the ground?
45
A 2400 kg truck is going around a curve with a radius of 80 meters. The speed of the truck is a constant 21 m/s. What it the acceleration of the truck, to the nearest TENTH in m/s2?
5.5
A 600 kg roller coaster is going around vertical loop with a radius of 10 meters. The speed of the coaster is 14 m/s at the top of the loop. What it the magnitude of the GRAVITATIONAL force on the roller coaster, to the nearest whole number of newtons?
5880
Two forces are at right angles to each other. In order to get the sum of the two forces
Draw them to scale or add using trig
If two vectors have different magnitudes and opposite directions, what is the sum of the two vectors.
Subtract the magnitudes and keep the direction of the larger vector. (add the vectors but make one of them negative.)
A ball is rolled across a table and flies off the end. At that point it becomes a projectile. Which statement is correct?
The time of the flight is determined ONLY by the height of the table.
The sum of two or more vectors is called the
resultant
In projectile motion, the horizontal component of the motion has constant velocity, and the vertical component has constant ___.
acceleration
Neglecting friction, if a Cadillac and Volkswagen start rolling down a hill together, the heavier Cadillac will get to the bottom
at the same time as the VW
Assuming they have the same amount of friction, if a massive Cadillac and light Volkswagen start rolling down a hill together, the heavier Cadillac will get to the bottom
before the VW
Imagine you are traversing a vertical loop-the-loop on a motorcycle. If you maintain a constant speed at which point, if any, will you experience the greatest sensation of weight?
bottom
In which of these paths may the speed stay the same for the entire motion?
circular; as in a car going around a curve
Vectors must include magnitude and
direction
As a car goes around an unbanked curve, what force supplies the centripetal acceleration?
friction
Every time you go around a curve in your car you need a centripetal force
friction
When the earth is nearer the sun in winter its speed compared to its speed when it is farther from the sun insummer is
greater
In projectile motion, the range is the horizontal component, and the ____ is the vertical component.
height or altitude
What are the units for centripetal acceleration?
m/s2
A baseball player throws a ball horizontally at 30 m/s from a height of 2.1 meters. Another player throws a ball at 20 m/s from the same height. Which will hit the ground first, if the friction is the same on both of them?
neither, they will hit at the same time
What is the path of a projectile launched in a gravitational field?
parabola
