When you sit in a chair there is necessarily a reaction force to the gravitational force acting on your body. Which of the following best describes this reaction force?
1.the force of gravity you exert on the Earth
2.the force you exert downward on the seat of the chair
3.the normal force exerted by the chair onto you
4.none of these forces
[Ques. 2] A race car moving quickly around a track collides with a mosquito, which splatters on the car's windshield. Which object experiences a greater magnitude acceleration?
1.Both experience the same acceleration.
2.the race car
3.the mosquito
4.One cannot tell, you need to know the speeds of the mosquito and the race car.
[Ques. 3] A race car moving quickly around a track collides with a mosquito, which splatters on the car's windshield. Which object experiences a greater magnitude impact force?
1.Both experience the same force.
2.One cannot tell, you need to know the speeds of the mosquito and the race car.
3.the mosquito
4.the race car
[Ques. 4] A model rocket of mass, m, is fired upward from a launch pad with some initial speed, v. A gravitational force is exerted on the rocket
1.at all points in its motion except at it highest point.
2.at all points in its motion.
3.at no points in its motion.
4.at none of these choices.
[Ques. 5] You push an object, initially at rest, across a frictionless floor with a constant force for a time interval, t, which results in a final speed of v for the object. You repeat the experiment, but with a force that is half as large. What time interval is now required to reach the same final speed?
1. 4t
2. t
3. t/2
4. 2t
[Ques. 6] An object accelerates when it experiences a non-zero net force. Which of the following statements is always true?
1.The object moves in the direction of the net force.
2.The object's velocity increases.
3.The object's velocity is in the same direction as its acceleration.
4.The object's acceleration is in the same direction as the net force that acts upon it.
[Ques. 7] An object moves with a constant velocity. Which of the following cannot be true for the object?
1.No forces act on the object.
2.A single force acts on the object.
3.Two forces act on the object.
4.Three forces act on the object.
[Ques. 8] Consider the following two statements and then select the option below that is correct.
i. It is possible for an object to move in the absence of forces acting on the object.
ii. It is possible to have forces acting on an object in the absence of motion of the object.
1.The second statement is the only correct one.
2.Both statements are correct.
3.Neither statement is correct.
4.The first statement is the only correct one.
[Ques. 9] A sailor drops a wrench from the top of a sailboat's
mast while the boat is moving steadily and rapidly in a straight line. Where will the wrench hit the deck?
1.at the base of the mast
2.behind the mast, along the direction opposite to the motion of the boat
3.in front of the mast, along the direction of the motion of the boat
4.impossible to tell
[Ques. 10] Determine which of the following objects obey the equations of projectile motion developed in this chapter.
i. A ball is thrown in an arbitrary direction.
ii. A jet airplane crosses the sky with its engines thrusting the plane forward.
iii. A rocket leaves the launch pad.
iv. A rocket moving through the sky after its engines have failed.
v. A stone is thrown underwater.
1.(i) and (v) only
2.(ii), (iii) and (iv) only
3.(i) and (iv) only
4.All of them obey the equations of projectile motion.
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