3.1) Which of the following statements about scientific methods / theories is correct?
(1/0/0)
a) A scientific theory must be able to
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a) A scientific theory must be able to be proven.
b) A scientific theory has been derived from known facts and always applies.
c) A scientific method should give different results depending on who performs the method.
d) Knowledge of our surroundings usually emerges through an interplay between theory and experiment.
2) The sides of a straight block are measured to 3,202 cm; 0.0012 cm and 11.2 cm, respectively. Calculate the volume of the straightening block and enter it with the correct number of value digits.
(2/0/0)
Number of words: 0
3) A 9.2 dm long and evenly thick rod rests on a support. 0.55 dm from one end, a dynamometer is hung so that the rod will hang horizontally. Then the dynamometer shows 4.4 N. How much does the bar weigh?
(1/1/0)
Number of words: 0
4) A bar AB that is homogeneous and evenly thick has a length of 2.70 m and is rotatable about an axis at A. The bar weighs 25 kg and is kept in equilibrium by a force F which has its point of attack in B. is 45 degrees. How big is the force F?
(1/1/0)
Saved!
25 * 9.82 = 245.5 N
Number of words: 6
5) A trolley rolls at a constant speed to the right. On the cart is an upward cannon that suddenly shoots a bullet. The carriage continues to the right with the same speed as before. Where does the bullet end up when it falls? For a detailed reasoning.
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Number of words: 0
6) A river is 200 m wide. The water in the river flows at a speed of 2.5 m / s. A motorboat steers across the river at its maximum speed, which in stagnant water is 5.0 m / s. The boat is constantly heading perpendicular to the banks of the river. Where does the motorboat land on the other shore?
(2/0/0)
Number of words: 0
7) A ball with a mass of 2.0 hg moves at a constant speed in a circular path. The radius of the track is 1.5 m and it takes the ball 3.0 seconds to move one turn. How big is the centripetal force?
(1/1/0)
Number of words: 0
8) A bullet moves at a constant speed. Can we then safely say that the resultant of the forces acting on the bullet is zero? Motivate and discuss your answer.
(0/1/1)
Number of words: 0
9) A conductor is located between the poles of a permanent magnet. The current in the conductor goes in the direction of the plane of the paper (away from the reader). How is the force acting on the leader directed?
(1/0/0)
a) To the right of the figure
b) To the left in the figure
c) Downwards in the figure
d) Upwards in the figure
10) Protons enter horizontally from the left between two large metal plates at a speed v = 0.80 Mm / s. The plates are connected to a voltage source with the pole voltage U. Between the plates there is a homogeneous magnetic field with a flux density of 38 mT directed perpendicular to the plane of the paper. The distance between the plates is 1.5 cm. They want the protons to continue with unchanged direction and speed between the plates. Which of the plates should be connected to the positive pole of the voltage source and how large should the voltage U be?
(0/2/0)
Number of words: 0
11) The magnetic flux Φ through a 700-speed coil decreases linearly with time according to the diagram below. Calculate the voltage across the coil at time t = 1.0 ms.
12) The current in a coil with an inductance of 35 mH has a growth rate of 6.2 A / s at a given moment. What is the instantaneous value of the ems induced in the coil?
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6.Directions: You are part of a fireworks crew assembling a local fireworks display.
There are two parts to the fireworks platforms:
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rts to the fireworks platforms: one part is on the ground and the
other part is on top of a building. You are going to graph all of your results on one
coordinate plane. Make sure to label each graph with its equation. Use the following
equations to assist with this assignment.
• The function for objects dropped from a height where t is the time in
seconds, h is the height in feet at time it t, and 0 h is the initial height is
2
0 ht t h ( ) 16 =− + .
• The function for objects that are launched where t is the time in seconds, h is
the height in feet at time t, 0 h is the initial height, and 0 v is the initial velocity
in feet per second is 2
0 0 ht t vt h ( ) 16 =− + + .
Select the link below to access centimeter grid paper for your portfolio.
Centimeter Grid Paper
Task 1
First, conduct some research to help you with later portions of this portfolio
assessment.
• Find a local building and estimate its height. How tall do you think the
building is?
• Use the Internet to find some initial velocities for different types of fireworks.
What are some of the initial velocities that you found?
Task 2
Respond to the following items.
1. While setting up a fireworks display, you have a tool at the top of the
building and need to drop it to a coworker below.
a. How long will it take the tool to fall to the ground? (Hint: use the first
equation that you were given above, 2
0 ht t h ( ) 16 =− + . For the building’s
height, use the height of the building that you estimated in Task 1.)
b. Draw a graph that represents the path of this tool falling to the
ground. Be sure to label your axes with a title and a scale. Your graph
should show the height of the tool, h, after t seconds have passed.
Label this line “Tool”.
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7.1. A ball is thrown with an initial speed of 20 m/s at an angle of 60° to the ground.
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ance is negligible, what is the ball’s speed at the instant it reaches its maximum height from the ground?
A. - 20 m/s
B. 0 m/s
C. + 17.3 m/s
D. + 10 m/s
E. + 20 m/s
2. A rhino charges full speed at a car with an initial velocity of 15 m/s. When the rhino collides with the car, it crumples in by 1 m before the rhino comes to a complete stop. What acceleration did the rhino feel as it came to a stop?
A. - 112.5 m/s^2
B. - 7.5 m/s^2
C. - 30 m/s^2
D. + 112.5 m/s^2
E. + 30 m/s^2
F. + 7.5 m/s^2
3. Two students want to determine the speed at which a ball is released when thrown vertically upward into the air. One student throws the ball into the air while the other student measures the total time that the ball is in the air. The students use a meterstick to measure the release height of the ball. Which of the following equations should the students use to determine the speed at which the ball was released? *
A. Use y final = y initial+ v initial *t + (1/2)*a*t^2 from the moment in time in which the ball was released to the moment in time in which the ball reaches its highest point.
B. v final^2 = v initial ^2 + 2a(????y) from the moment in time in which the ball was released to the moment in time in which the ball hits the ground.
C. Use y final = y initial+ v initial *t + (1/2)*a*t^2 from the moment in time in which the ball was released to the moment in time in which the ball hits the ground.
D. v final^2 = v initial ^2 + 2a(????y) from the moment in time in which the ball was released to the moment in time in which the ball reaches its highest point.
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