Makayla is talking to Mia about the whether we ever landed on the Moon. Mia says,” I have a theory about that.” Using 3 – 4 complete sentences, what is wrong with Mia’s use of the term “theory” in this instance?
Choose ONE of the scenarios below, then design an experiment and describe a procedure to enable you to make an estimate of the average speed. Your description should include the materials you would need and how you would use them to collect the data you need.
A baseball thrown from outfield to home plate
A hand moving back and forth as fast as possible
The tip of a swinging baseball bat
An eye blinking
A whisker growing
There are many familiar situations in whichthe net force on a body is zero and yet the body moves with a constant velocity. One example is described below:
A car traveling at constant speed on a straight road has the force of the road on the tires just balanced by the force of air friction. If the gas pedal is depressed further, the tires will push against the road harder and the road will push against the tires harder; so the car will accelerate forward – until the air friction builds up enough to balance the greater drive force. Give another example of a body moving with constant velocity under balanced forces. Specify the cause of each force on the body and explain how these forces could be changed to affects the body’ motion.
Cleo and Clare are looking from their balcony to a swimming pool below that is located 15 m horizontally from the bottom of their building. They estimate the balcony is 45 m high and wonder how fast they would have to jump horizontally to succeed in reaching the pool. What calculations would you show to help them determine the answer? Evaluate the practicality of their being able to succeed at jumping into the pool.
An airplane has a gun that fires bullets straight ahead at the speed of 600 miles per hour when tested on the ground while the plane is stationary. The plane takes off and flies east at 600 miles per hour. Explain whether each of the following is possible for the pilot to measure:
When fired directly ahead the bullets move eastward at a speed of 1200 miles per hour
When fired in the opposite direction (by turning the gun westward, but not the plane), the bullets drop vertically downward
If fired vertically downward (by turning the gun downward, but not the plane), the bullets move eastward at 600 miles per hour while they fall.
A falling 50-kg skydiver experiences an upward acceleration of 6.2 m/s2 when she opens her parachute. Show (by calculation) how much drag force is produced by the parachute.
In three scenarios a truck is towing a boat on a trailer. Using 3 – 4 complete sentences indicate which scenario(s) (if any) is the force of the truck on the trailer greater than the force of the trailer on the truck:
Scenario A: masstruck = 1000 kg, massboat and trailer = 500 kg; velocity = 20 m/s
Scenario B: masstruck = 800 kg, massboat and trailer = 800 kg; velocity = 20 m/s
Scenario C: masstruck = 500 kg, massboat and trailer = 1000 kg; velocity = 15 m/s
A bug and the windshield of a fast-moving car collide. Indicate whether each of the following statements is True or False (1 point each)
The forces of impact on the bug and on the car are the same magnitude.
The impulses on the bug and non the car are the same magnitude
The changes in speed of the bug and of the car are the same magnitude.
The changes in momentum of the bug and of the car are the same magnitude.
The accelerations of the bug and the car are the same magnitude.
Betty and Bianca weigh the same amount and they climb a flight of stairs. Betty climbs the stairs in 30 seconds. Bianca climbs the stairs in 40 seconds. In terms of force, work and power, evaluate which of the three quantities (if any) is greater for Betty or for Bianca? Justify your answers using 3 – 4 complete sentences.
This graphic shows a scene from a trapeze act. Write 3 – 4 complete sentences to describe the physics pictured in this scene. Use the terms inertia, centripetal acceleration, force, gravity, and velocity in your description.
Using 6400 km as the radius of Earth, calculate how high above Earth’s surface you would have to be in order to weigh 1/16th of your current weight. Show all work leading to your answer OR describe your solution using 3 -4 complete sentences.
The sun’s mass is about 2.7 x 107 times greater than the moon’s mass. The sun is about 400 times farther from Earth than the moon. How does the gravitational force exerted on Earth by the sun compare with the gravitational force exerted on Earth by the moon?
Can you get younger by traveling at speeds near the speed of light? Explain using 3 or more complete sentences.
A beam of light and a baseball are both affected by gravity. Why is the path of the baseball very different than the path of the light beam? Use 3 – 4 complete sentences in your explanation.
When a steadily-flowing gas flows from a larger-diameter pipe to a smaller-diameter pipe, what causes the pressure in the smaller pipe to drop? Use 3 – 4 complete sentences to explain your answer.
When a 3-kg iron skillet is heated on the stove, it becomes hot very quickly. When 3 kg of water is heated on the stove it heats up slowly. What is the reason for this difference? Support your answer using 3 – 4 complete sentences.
When a wave crosses a surface at an angle from one medium into another, why does it change directions as it moves across the boundary into the new medium? Use 3 – 4 complete sentences in your own words to explain.
Suppose a piano tuner hears 2 beats/second when listening to the combined sound from the tuning fork and the piano note being tuned. After slightly loosening the string, she hears 1 beat/second. Should she continue to loosen the string or tighten it in order to get it “in tune”? Defend your answer with 3 – 4 complete sentences.
What conditions must exist for a converging lens to produce a real image of an object that is larger than the object itself? Please respond with 3 - 4 complete sentences.
Suppose the thickness of an oil film on water is just the right thickness for canceling red light. What color will your eye see? Explain using 3 – 4 complete sentences.
A hard-rubber or plastic comb rubbed against wool can often be shown to have a static charge. Why does a metal comb not readily show a static charge when rubbed against wool? Use 3 – 4 complete sentences in your answer.
Two electrically-charges spheres are suspended from insulated threads a certain distance from each other. There is a certain amount of electrostatic force between them. Describe
specifically (not just increase or decrease) what happens to this force in each of the scenarios below (1 pt. ea.):
The charge on one sphere is reduced by half
The charge on both spheres is doubled
The distance between the spheres is increased by a factor of three
The distance between the sphere is decreased to one-fourth
The charge of each sphere is doubled and the distance between them is doubled
Three identical light bulbs are connected in series, then are disconnected and arranged in parallel. For each of the scenarios below indicate what changes (if any) take place (1 pt. ea.):
Total resistance of the circuit
Total current of the circuit
Power dissipated by the circuit
Voltage used by one of the light bulbs
Resistance of one of the light bulbs
Using 3 – 4 sentences, explain, in your own words, two ways you could cause an electrical current using only a wire and a horseshoe magnet.
Using 3 - 4 complete sentences, explain the role of both types of transformers in getting electric energy from an electric power plant(coal-fired, natural gas or nuclear) to our homes.
In what way does the photoelectric effect support the particle theory of light? Use 3 – 4 complete sentences in your own words to explain.