Which of the following expresses a principle which was initially stated by Galileo and was later incorporated into Newton's laws of motion?
a. An object's acceleration is inversely proportional to its mass.
b. For every action there is an equal but opposite reaction.
c. The natural condition for a moving object is to remain in motion.
d. The natural condition for a moving object is to come to rest.
[Ques. 2] If we know an object is moving at constant velocity, we may assume:
a. the net force acting on the object is zero.
c. the object is accelerating.
b. there are no forces acting on the object.
d. the object is losing mass.
[Ques. 3] The net force on an object in the positive x direction. Consider the following statements: i) The object can be moving in the negative x direction. ii) The object can be speeding up. iii) The object can be slowing down. iv) The object can be moving in the positive y direction. Which of the statements are true?
a. (i) and (ii)
b. (ii) and (iii)
c. (iii) and (iv)
d. Choose this answer if all the statements are true.
[Ques. 4] Five boys are pushing on a snowball, and each is pushing with a force of 20.0 N. However, each boy is pushing in a different direction. They are pushing north, northeast, east, southeast, and south. (Each boy is pushing at an angle of 45.0 relative to his neighbor.) What is the magnitude of the total force on the ball?
a. 54.2 N
c. 24.1 N
b. 48.3 N
d. 0 N
[Ques. 5] A physics student is riding on a train traveling north. Having read about inertia, the student performs an experiment with a golf ball. He reaches over the aisle and drops the ball from rest. Instead of hitting the floor directly below the student's hand, it hits to the north, i.e., forward of that position. Which of the following might be the cause for this to happen?
a. The train is moving at constant velocity.
c. The train is slowing down.
b. The train is speeding up.
d. Whatever the cause, it cannot be any of the answers given.
[Ques. 6] On a velocity-time graph for a particle, suppose the plot starts at some positive velocity and then follows a straight line to zero at a later time. Which of the following must be true about a position vs. time graph for this same time interval?
a. The curve will start at a positive position value and follow a straight line to zero at the later time.
b. The curve will rise steeply at first and as time goes on will level out approaching its highest position value at the later time.
c. The curve will drop steeply at first and as time goes on will approach its lowest position value at the later time
d. The curve will start at the zero of position and follow a straight line to its highest position at the later time.
[Ques. 7] On a position-time graph for a particle, suppose the plot starts at some positive position and as the time goes on the curve gets steeper and steeper while curving upwards. Which of the following must be true?
a. The speed of the particle is constant.
c. The speed of the particle is decreasing.
b. The acceleration of the particle is constant.
d. The acceleration of the particle is positive.
[Ques. 8] A car is moving in the positive direction along a straight highway and accelerates at a constant rate while going from point A to point B. If the acceleration is positive, increasing the speed of the car, when does the position where the average speed equals the instantaneous speed occur during the time interval from A to B? Assume the time interval is T.
a. T/2 from the start of the interval
c. after T/2 from the start of the interval
b. before T/2 from the start of the interval
d. It depends on the speed at the start of the time interval.
[Ques. 9] A car is moving along a straight highway and accelerates at a constant rate while going from point A to point B. If the acceleration is positive, increasing the speed of the car, where does the position where the instantaneous speed equals the average speed occur for the interval from A to B?
a. midway between A and B
c. closer to B than to A
b. closer to A than to B
d. Any of the answers could be correct depending on the original speed.
[Ques. 10] A runner circles a track of radius 100 m in 100 s moving at a constant rate. If the runner was initially moving east, what has been the runner's average acceleration when halfway around the track?
a. At a constant rate, the average acceleration would be zero.
b. 0.13 m/s2, south
c. 0.25 m/s2, west
d. No answer is correct.
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