Objective 5 Motion, Forces, and Energy. IPC 4A – Calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines. Common measurements and symbols. Using the formula chart. 1. Circle what you are asked to find
Objective 5Motion, Forces, and Energy
IPC 4A – Calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines.
1. Circle what you are asked to find
2. Underline given facts with numbers and units and write the symbol above it.
3. Identify the formula(s) you will use from the formula chart
4. Rearrange the formula for what you’re asked to find.
5. Put in numbers for symbols and solve.
6. Check that you answered the question asked.
When a formula is not solved for the variable you are trying to find, then you need to rearrange it until your variable is alone on one side of the equation.
Example, the speed formula is:
If you are given speed and time and want to find distance, what would the formula be?
Here, you divided d by t. To move t to the other side, do the opposite, multiply by it.
t cancels on the right side
And you are left with the formula for d.
How fast an object is traveling.
Velocity has direction, speed does not.
The change in velocity
If an object is moving at a constant speed, acceleration = 0
Negative acceleration (deceleration) means the object is slowing down.
Using force to move an object a certain distance.
If there is no movement, there is no work done. If distance = 0, work = 0
Does not depend on the time it takes to do the work
If Distance = 0,
Work = 0.
The rate at which work is done.
More power means the same work can be done faster.
What is the power of this motor?
Power = Work/time
Time = 5 s
We must find the work first!
Work = Force x distance
= 10 N x 2m = 20 J
Power = Work/time
The product of an object’s mass and velocity.
Can be thought of as how difficult it is to stop a moving object.
A stopped object has zero momentum.
In collisions, total momentum does not change. The momentum of the objects (together) before the collision is the same as the momentum of the objects (together) after the collision.
No speed = stopped
Constant speed away from a point
Constant speed toward a point
The line gets less steep – slowing down
The line gets steeper – speeding up
Two ice hockey players are skating directly at each other. The first has a mass of 87 kg and is skating at a constant speed of 2.6 m/s. The second skater has a mass of 78 kg. How fast must the second skater be skating in order to have a momentum similar to the first skater?
A 2.3 m/s
B 2.9 m/s
C 3.4 m/s
D 5.2 m/s
How much force is needed to accelerate a 1,300 kg car at a rate of 1.5 m/s2?
F 867 N
G 1,950 N
H 8,493 N
J 16,562 N
An ant crawled from Point A to Point B in 4.0 seconds. To the nearest tenth, what was the ant’s speed in centimeters per second?
Assume the ant traveled 5.6 cm.
The diagram represents the total travel of a teacher on a Saturday. Which part of the trip is made at the greatest average speed?
A car traveled 150 km in 2.5 hours. What was its average speed in km per hour? Record and bubble in your answer on the answer document.
Which bike rider has the greatest momentum?
A A 40 kg person riding at 45 km/h
B A 50 kg person riding at 35 km/h
C A 60 kg person riding at 25 km/h
D A 70 kg person riding at 15 km/h
IPC 4B – Investigate and describe [applications of] Newton’s laws such as in vehicle restraints, sports activities, geological processes, and satellite orbits.
Unbalanced forces cause an object to accelerate (speed up, slow down or change direction) in the direction of the largest force.
Friction is a force that acts in the opposite direction to the motion of a moving object.
Newton’s First Law: An object at rest will remain at rest and an object in motion will remain in motion at a constant velocity unless acted upon by an unbalanced force.
Orbits and Inertia
The force on the ball and the force on the cannon are equal (See 3rd Law).
F = ma
The ball’s mass is lower, so its acceleration is higher.
The cannon’s mass is greater, so its acceleration is lower.
Newton’s Third Law: For every action force, there is an equal and opposite reaction force.
In the event of an accident, air bags and seat belts may help reduce injury to a passenger by decreasing the force that stops the passenger’s motion. The force is reduced because the seat belts or air bags decrease the —
A mass of the passenger
B acceleration of the passenger
C reaction time of the driver
D speed of the vehicle
The illustration above shows a student about to throw a ball while standing on a skateboard. Which illustration below correctly shows the skateboard’s direction of motion after the student releases the ball?
The table shows times required for the same toy car to travel 10 m across an identical section of a floor after it is pushed. The difference in times was probably caused by differences in —
A force exerted
B surface friction
C air resistance
D car mass
IPC 5A – Demonstrate wave types and their characteristics through a variety of activities such as modeling with ropes and coils, activating tuning forks, and interpreting data on seismic waves.
Types of Waves
2. Longitudinal (compression)
Parts of a Wave
Calculating Wave Speed
Velocity of a wave = Wavelength • Frequency
Measured in Hz
A surfer wishing to ride a big wave is most
interested in a wave’s —
At 0°C sound travels through air at a speed of 330 m/s. If a sound wave is produced with a wavelength of 0.10 m, what is the wave’s frequency?
F 0.0033 Hz
G 33 Hz
H 330 Hz
J 3300 Hz
Which illustration best demonstrates compression waves?
IPC 6A – Describe the law of conservation of energy.
mechanical energy- energy of motion—hitting a ball, walking, blood flowing through your vessels
heat energy- internal motion of atoms; usually results from friction—causes phase & temperature changes
chemical energy- energy that exists in the bonds that hold atoms together—starting a fire, burning fuel, digesting food
nuclear energy- energy associated with the nucleus of an atom; produces the sun’s energy due to nuclear fusion--hydrogen changes to helium
electromagnetic energy- energy associated with moving charges—microwaves, X-rays
The U.S. Naval Research Laboratory has created an experimental marine fuel cell that could produce enough electricity to power ocean-monitoring devices. This fuel cell runs on seawater and sediment, with the help of plankton. Some plankton on the surface of ocean sediments use dissolved oxygen to break down organic matter, releasing energy; this is an aerobic process. The plankton in the deeper sediments break down organic matter without using oxygen; this is an anaerobic process. These two processes create a difference in voltage between the surface of the sediment and the sediment farther down in the seabed. The voltage difference can be used to produce electricity-up to 5.0 x 10–2 watts of power. Energy supplied by this type of fuel cell can be obtained as long as there is organic matter in the sediment. Fuel cells powered by plankton from the seabed can be used to operate instruments that monitor ocean currents and water temperature. These fuel cells get their energy by converting —
F chemical energy to electrical energy
G electrical energy to mechanical energy
H hydroelectric energy to geothermal energy
J mechanical energy to chemical energy
IPC 6B – Investigate and demonstrate the movement of heat through solids, liquids, and gases by convection, conduction and radiation.
1. conduction- heat is transferred through a substance, or by the direct contact of molecules
conductors- substances that conduct heat better & more rapidly than others (silver, copper, iron)
insulators- substances that do not conduct heat easily (glass, plastic, wood, rubber)—wearing several layers of clothing in extremely cold weather
2. convection- takes place in liquids & gases as up-and-down movements called convection currents.
3. radiation- heat energy transfer through empty space
Mud at the bottom of a fishpond has a temperature of 15°C. After a week of colder air
temperatures, the mud temperature drops to 12°C. Which of the following methods of heat transfer is most responsible for the change in the mud temperature?
A Water convection
B Air conduction
C Water reflection
D Ground radiation
The primary way liquids and gases transmit heat is by the process of —
A man who was sleeping wakes up because he hears the smoke alarm go off in his house. Before opening the bedroom door, the man feels the door to see whether it is warm. He is assuming that heat would be transferred through the door by —
IPC 6F – Investigate and compare series and parallel circuits.
IPC 6F – Investigate and compare series and parallel circuits. (10th grade only)
To have an electric circuit, you need:
What happens if the first light bulb burns out?
What happens if the first light bulb burns out?
Which switch, if opened, will cause the lightbulb to stop glowing?
What is the current in a copper wire that has a resistance of 2 ohms and is connected to a 9-volt electrical source?
F 0.22 amp
G 4.5 amps
H 11.0 amps
J 18.0 amps
How much current is flowing through this circuit?
A 0.32 A
B 3.1 A
C 4.0 A
D 12.5 A
Which circuit is built so that if one lightbulb goes out, the other three lightbulbs will continue to glow?