6.5 CHAPTER 6. MOTIONIN TWO DIMENSIONS
- [IEB 2002/11 HG1]An observer on the ground looks up to see a
bird flying overhead along a straight line on bearing 130◦(40◦S of
E). There is a steady wind blowing from east towest. In the vector
diagrams below, I, II andIII represent the following:
I the velocity of the bird relative to the air
II the velocity of the air relative to the ground
III the resultant velocityof the bird relative to theground
Which diagram correctly shows these three velocities?
N
40 ◦|||
|||N40 ◦
|||
|
||DN40 ◦|||
|||N
130 ◦||||||A B C- [SC 2003/11] A ballX of mass m is projected vertically upwards at a
speed uxfrom a bridge 20 m high. A ball Y of mass 2 m is projected
vertically downwards from the same bridge at a speed of uy. The two
balls reach the water atthe same speed. Air friction can be ignored.
Which of the following is true with reference to the speeds with which
the balls are projected?
(a) ux=^12 uy
(b) ux= uy
(c) ux= 2uy
(d) ux= 4uy - [SC 2002/03 HG1] Astone falls freely from rest from a certain height.
Which one of the following quantities could berepresented on the
y-axis of the graph below?
Y
(a) velocity time
(b) acceleration
(c) momentum
(d) displacement- A man walks towards the back of a train at2 m·s−^1 while the train
moves forward at 10 m·s−^1. The magnitude of the man’s velocity
with respect to the ground is
(a) 2 m·s−^1
(b) 8 m·s−^1
(c) 10 m·s−^1
(d) 12 m·s−^1