A car’s initial velocity is 50.0 km/h in the direction 60.0° north of east, and its final velocity is 70.0 km/h in the direction 40.0° south of east. If the time period for this journey is 30.0 minutes, what is the magnitude of the car’s average acceleration? Group of answer choices
186 km/h/h
240 km/h/h
92.8 km/h/h
3.94 km/h/h
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The figure shows a cut-away drawing of a thermos bottle (also known as a Dewar flask), which is a device designed specifically to slow down all forms of heat transfer. Explain the functions of the various parts, such as the vacuum, the silvering of the walls, the thin-walled long glass neck, the rubber support, the air layer, and the stopper.
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1) While a lawn mower moves forward 2 meters, a man pulls on the handle of the lawnmower with a force of 100 Newtons. The angle between the displacement of the lawn mower and the direction of the applied force is 135.6 degrees. How much work was done on the lawnmower by the man?
A) 200 Joules
B) - 200 Joules
C) zero
D) - 141 Joules
E) 141 Joules
2) If the lawn-mower had 300 Joules of kinetic energy before the man pulled on it, about how much kinetic energy does it have after the work done by the man? (Assume there are no energy losses to friction).
A) 440 Joules
B) 500 Joules
C) 300 Joules
D) negative kinetic energy
E) 160 Joules
3) A car changes its speed from 30 mph to 90 mph. How many times greater is its final kinetic energy compared to its initial kinetic energy?
A) eight times as much
B) four times as much
C) twice as much
D) three times as much
E) nine times as much
4) Assume that the car changes chemical potential energy (gasoline) into kinetic energy with the same efficiency at all speeds. How many times more gas will it take far the car to go from 30 to 90 mph, compared to going from zero to 30 mph?
A) twice as much
B) nine times as much
C) three times as much
D) six times as much
E) the same amount
F) eight times as much
5) The scalar product of two vectors is equal to ...(choose all correct responses).
A) the magnitude of the first vector times the magnitude of the
second vector times the cosine of the angle between the
vectors
B) the magnitude of one of the vectors multiplied by the component
of the other vector that is parallel to the first vector
C) a vector quantity
D) the product of a scalar and a vector
E) none of the other answers is correct
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The answer and solutions are not given. Solve everything from a through f.
An automobile takes 9.89 seconds to accelerate from rest to 60 miles per hour. a) Find the automobile's acceleration (assuming that is constant) and b) the distance traveled in reaching 60.0 miles per hours. Assuming that this acceleration remains constant over 0.25 miles, predict c) the time it takes to cover this distance and d) the car's velocity at the end. e) convert this velocity to miles per hour. f) sketch graphs of position, velocity, and acceleration versus time for this automobile.
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Four identical masses of 2.6 kg each are located at the corners
of a square with 1.2 m sides. What is the net force on any one of
the masses?
? ?? N toward ...............opposite corner
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A subway train starts from rest at a station and accelerates at a rate of 2.00 m/s2 for 14.0 s. It runs at constant speed for 66.0 s and slows down at a rate of 4.00 m/s2 until it stops at the next station. Find the total distance covered.
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Two satellites are in circular orbits around the earth. The orbit for satellite A is at a height of 555 km above the earth’s surface, while that for satellite B is at a height of 778 km. Find the orbital speed for (a) satellite A and (b) satellite B.
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Water flows vertically out of a circular faucet that has a diamter d=0.050m, height = 0.55m, speed after falling that height = 3.58 m/s.
What is the volume of water that exits the faucet in 2.0 seconds? Please write formula used to solve this eq.
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Why is it that when you put something metal in the microwave, you get a firework display, and yet the inside of the microwave is made out of metal?
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Describe the differences between circular motions and elliptical motions. Explain how Newton’s universal gravitational law can be applied to study the interplanetary motions.
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Waves travel at different velocity in different medium. How does wave velocity effect wave frequency?
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what would the kvl be if -330i1-470i2-860i2+9=0 and -6-12-560i3-860i2+9=0 and -330i1-470i1+560i3+12+6=0 and i2=i1+i3.find i1, i2, i3.
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How did shortening the length of the spring affect the resonant frequencies? How does this confirm the relationship v = ? f when velocity is constant? And how musical instruments create higher and lower tones. Use a string instrument as an example.
I can't explain above question well....When the wavelength becomes short, it increases its frequency.
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a ray of yellow light crosses the boundary between glass and air, going from glass to air. If the angle of incidence is 30 degrees, what is the angle of refraction
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A ball is kicked horizontally with 15 m/s initial speed from a cliff. The ball lands 75 m away from the base of the cliff (R = 75m). What is the height of the cliff? What is the hitting velocity (the velocity of the ball before it hits the ground)? What is the total time of flight?
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