Gayle runs at a speed of 3.30 m/s and dives on a sled, initially at rest on the top of a frictionless snow-covered hill. After she has descended a vertical distance of 5.00 m, her brother, who is initially at rest, hops on her back and together they continue down the hill. What is their speed at the bottom of the hill if the total vertical drop is 15.0 m? Gayle's mass is 47.0 kg, the sled has a mass of 5.25 kg and her brother has a mass of 30.0 kg.
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A block with mass m1 = 9.4 kg is on an incline with an angle θ = 34° with respect to the horizontal. For the first question there is no friction between the incline and the block. 1) When there is no friction, what is the magnitude of the acceleration of the block? m/s2 2) Now with friction, the acceleration is measured to be only a = 3.73 m/s2. What is the coefficient of kinetic friction between the incline and the block? 3) To keep the mass from accelerating, a spring is attached with spring constant k = 168 N/m. What is the coefficient of static friction if the spring must extend at least x = 16 cm from its unstretched length to keep the block from moving down the plane? 4) The spring is replaced with a massless rope that pulls horizontally to prevent the block from moving. What is the tension in the rope? N 5) Now a new block is attached to the first block. The new block is made of a different material and has a coefficient of static friction μ = 1.01. What minimum mass is needed to keep the system from accelerating? kg
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A 6.60 −μC particle moves through a region of space where an electric field of magnitude 1350 N/C points in the positive x direction, and a magnetic field of magnitude 1.25 T points in the positive z direction. If the net force acting on the particle is 6.21×10−3 N in the positive x direction, find the components of the particle's velocity. Assume the particle's velocity is in the x-y plane.
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How do random motion and gravitational collapse combine to convert giant molecular clouds into open star clusters over a long period of time?
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To describe and analyze motion in 2D (or higher), the use of vectors is the common method used. From your work with vectors, past and present, do you find the vector method a good (even best) way to analyze quantities in 2D? Are there other methods that could be used that will give the same results? From your own experience, what are the pros and cons in using the vector method?
Please no handwritten or typed responses - only typed answers.
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Describe house wiring and specify how parallel or series connections of bulbs and resistors affect the functions.
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A 72.0 kg swimmer jumps into the old swimming hole from a tree limb that is 3.95 m above the water.
Use energy conservation to find his speed just as he hits the water if he just holds his nose and drops in.
Express your answer to three significant figures.
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Part B
Use energy conservation to find his speed just as he hits the water if he bravely jumps straight up (but just beyond the board!) at 2.60 m/s .
Express your answer to three significant figures.
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Part C
Use energy conservation to find his speed just as he hits the water if he manages to jump downward at 2.60 m/s .
Express your answer to three significant figures.
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A kestrel dives from a stationary hover, 20 m above the ground, to catch its prey, typically mice, on the ground. (a) If the kestrel’s acceleration toward the ground is due solely to free fall, calculate how long it takes to reach the ground. (3 points) (b) A field mouse can run at a top speed of 10 km/h, which it achieves starting from rest in 1 s. Assuming that the only way for the mouse to survive the kestrels attack is to find shelter, calculate the maximum distance the mouse can be from shelter to survive if it sees the kestrel as it begins its dive. (3 points) The mouse, in fact, only first sees the kestrel when it is at the mid point of the dive 10m above the ground. (c) Based only on your intuition (and not on any calculation), estimate how far the mouse needs to be from shelter to survive now. (1 point) (d) Calculate how far the mouse needs to be from shelter to survive in the new situation.
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what is the frequency of a sound wave made by
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If Emily throws the ball at an angle of 30∘ below the horizontal with a speed of 14m/s, how far from the base of the dorm should Allison stand to catch the ball? Assume the vertical distance between where Emily releases the ball and Allison catches it is 8.0m.
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During a tennis match, a player serves the ball at 25.6 m/s, with the center of the ball leaving the racquet horizontally 2.34 m above the court surface. The net is 12.0 m away and 0.900 m high. When the ball reaches the net, (a) what is the distance between the center of the ball and the top of the net? (b) Suppose that, instead, the ball is served as before but now it leaves the racquet at 5.00° below the horizontal. When the ball reaches the net, what now is the distance between the center of the ball and the top of the net? Enter a positive number if the ball clears the net. If the ball does not clear the net, your answer should be a negative number. Use g=9.81 m/s2.
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The nucleus of 8Be, which consists of 4 protons and 4 neutrons, is very unstable and spontaneously breaks into two alpha particles (helium nuclei, each consisting of 2 protons and 2 neutrons). (a) What is the force between the two alpha particles when they are 3.40 10-15 m apart? Your response differs from the correct answer by more than 10%. Double check your calculations. N (b) What is the initial magnitude of the acceleration of the alpha particles due to this force? Note that the mass of an alpha particle is 4.0026 u. m/s2
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A passenger on a moving train walks at a speed of 1.60 m/s due north relative to the train. The passenger's speed with respect to the ground is 4.5 m/s at an angle of 35.0° west of north. What are the magnitude and direction of the velocity of the train relative to the ground? _______m/s direction ______ ° west of north
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the force exerted by a spring is given by the equation
where F is the force (in Newtons), xis the displacement of the spring from the equilibrium position (in centimeters), and k is a spring constant
Create an Excel worksheet showing force as a function of displacement for two springs whose spring constants are 0.1 N/cm and 0.5 N/cm. Use displacements ranging from 0 to 20 cm (i.e. let x = 0, 1, 2 … 20 cm).
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From the window of a building, a ball is tossed from a height y0 above the ground with an initial velocity of 7.90 m/s and angle of 19.0° below the horizontal. It strikes the ground 6.00 s later.
(a) If the base of the building is taken to be the origin of the coordinates, with upward the positive y-direction, what are the initial coordinates of the ball? (Use the following as necessary: y0. Assume SI units. Do not substitute numerical values; use variables only.)
xi =
yi =
(b) With the positive x-direction chosen to be out the window, find the x- and y-components of the initial velocity.
vi, x = _______ m/s
vi, y = _______m/s
(c) Find the equations for the x- and y-components of the position as functions of time. (Use the following as necessary: y0 and t. Assume SI units.)
x =_____ m
y = ____m
(d) How far horizontally from the base of the building does the ball strike the ground?
_______m
(e) Find the height from which the ball was thrown.
______m
(f) How long does it take the ball to reach a point 10.0 m below the level of launching?
Please show work
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