(Please use the scantron for Sec. ) Section I (2 points each) 1. Which force is

Question

(Please use the scantron for Sec. ) Section I (2 points each) 1. Which force is responsible for holding a car in an unbanked curve? Time: 2.5 hrs a) the car's weight b) the force of friction c) the reaction force to the car's weight d) the vertical component of the normal force e) the horizontal component of the normal force 2. A spaceship is in orbit around the earth at an altitude of 12 000 miles. Which one of the following statements best explains why the astronauts experience "weightlessness?" a) The centripetal force of the earth on the astronaut in orbit is zero newtons. b) The pull of the earth on the spaceship is canceled by the pull of the other planets c The spaceship is in free fall and its floor cannot press upwards on the astronauts. d) The force of gravity decreases as the inverse square of the distance from the earth's center. e) The force of the earth on the spaceship and the force of the spaceship on the earth cancel because they are equal in magnitude but opposite in direction 3. The pariation of g over the surface of the earth does not depend upon a the shape of the Earth. ) changes in elevation. c) rotation of the Earth. d) the subsurface structure of the Earth. 4. If the sum of two vectors equals zero, the magnitude of their difference is a) equal to the magnitude of either one. b) equal to twice the magnitude of either one. less than twice the magnitude of either one. d)) zero ls in a straight line covering a total distance of 90.0 miles in 60.0 minutes 5. A car trave

Explanation / Answer

1.b)

frictional force provides the necessary centripetal force to move in a curve on an unbanked road

2 c)

during free fall , the force equation is given as

mg - Fn = ma

here a = g

so mg Fn = mg

this gives , Fn = 0

so we feel weightlessness

4 d)

sum of two vectors is zero when they are equal in magnitude and opposite in direction

hence when we do the difference of the equal magnitudes of two vectors , we get 0

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