The speedometer of a car indicates a constant speed of 30 miles per hour. From this we can say that the acceleration of the car is
1) zero.
2) nonzero.
3) can't really say.
This is because
4) no net force is acting on the car.
5) any reading (other than zero) on the speedometer indicates acceleration.
6) the car may be changing its direction.
[Ques. 2] If an object is thrown downward from a tall cliff, its acceleration while falling (in the absence of air resistance) will be
1) less than 10 m/s2.
2) 10 m/s2.
3) greater than 10 m/s2.
This is evident from the fact that
4) gravitational force depends upon the state of motion of an object.
5) each successive second the speed of the object increases by an additional 10 m/s.
6) the object was not simply dropped but thrown, therefore having an initial acceleration of fall greater than zero.
[Ques. 3] To say that an object is being accelerated, means that
1) it is at rest,
2) it is moving,
3) it is either at a state of rest or a state of constant velocity,
4) its state of motion is changing,
and we define acceleration to be
5) a change in speed.
6) a change in velocity.
7) the rate at which speed changes.
8) the rate at which velocity changes.
[Ques. 4] The boat that will sail fastest in the intended direction is
1) 1,
2) 2,
3) 3,
4) 4,
and the boat that responds least to the wind is
5) 1.
6) 2.
7) 3.
8) 4.
[Ques. 5] A small railroad car is pulled by a rope as shown in the sketch (top view). The force F that the rope exerts on the car has a component along the track and another component perpendicular to the track.
Judging from the diagram, the larger of these two components would be
1) along the track.
2) perpendicular to the track.
These components will be equal if
3) the rope makes an angle of 45 with the track.
4) the rope is pulled in a direction along the track, rather than at an angle to it.
5) they form an action-reaction pair on the car.
6) but they can never really be equal.
[Ques. 6] The boat to make the fastest progress in its forward direction is boat
1) 1.
2) 2.
3) 3.
4) 4.
Boat 3 is not propelled in a forward direction because
5) the wind does not make impact with the sail.
6) there is no component of force parallel to the keel.
7) of air resistance on the front of the sail.
8) But it is propelled in a forward direction
[Ques. 7] Which of the sailboats shown sails fastest in its forward direction?
1) 1
2) 2
3) 3
4) None sails forward.
It is interesting to note that the force of the wind impact is
5) nonexistent on each sail.
6) greatest on 1.
7) greatest on 2.
8) greatest on 3.
[Ques. 8] Which of the sailboats shown sails the fastest in its forward direction?
1) 1
2) 2
3) 3
4) 4
It is interesting to note that
5) this is the only boat that sails forward.
6) only two of the boats sail forward.
7) three out of the four boats sail forward.
8) all sail forward, but at different speeds.
[Ques. 9] A block is pulled across a floor as shown in the vector diagram. The greater component of F is in the
1) horizontal direction,
2) vertical direction,
although both horizontal and vertical components would be of equal magnitude if vector F were
3) horizontal.
4) vertical.
5) at an angle of 45.
[Ques. 10] The weight of the barrel on the slope is shown by the vector which has components (not shown) parallel to the surface of the incline and perpendicular to the surface of the incline.
Judging from the slope of incline, the greater of these two components is
1) parallel to the slope.
2) perpendicular to the slope.
3) both the same.
4) need more information
If the slope of the incline were steeper, this component vector would
5) decrease.
6) remain the same.
7) increase.
8) again, can't really say.
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