Everything Science Grade 12
CHAPTER 6. MOTIONIN TWO DIMENSIONS 6.5
- A stone is thrown vertically upwards and it returns to the ground. If
friction is ignored, its acceleration as it reaches the highest point of its
motion is
(a) greater than just after it left the throwers hand.
(b) less than just beforeit hits the ground.
(c) the same as when itleft the throwers hand.
(d) less than it will be when it strikes the ground.
- An exploding device is thrown vertically upwards. As it reaches its
highest point, it explodes and breaks up into three pieces of equal
mass. Which one of the following combinations ispossible for the
motion of the three pieces if they all move in a vertical line?
Mass 1 Mass 2 Mass 3
A v downwards v downwards v upwards
B v upwards 2v downwards v upwards
C 2v upwards v downwards v upwards
D v upwards 2v downwards v downwards
- [IEB 2004/11 HG1]A stone is thrown vertically up into the air. Which
of the following graphsbest shows the resultantforce exerted on the
stone against time whileit is in the air? (Air resistance is negligible.)
Fres
t
A
0
Fres
0 t
B
Fres
t
C
0
- What is the velocity of a ball just as it hitsthe ground if it is thrown
upward at 10 m·s−^1 from a height 5 meters above the ground?
- [IEB 2005/11 HG1]A breeze of 50 km·hr−^1 blows towards the west
as a pilot flies his light plane from town A to village B. The trip from
A to B takes 1 h. He then turns west, flying for^12 h until he reaches
a dam at point C. He turns over the dam and returns to town A. The
diagram shows his flightplan. It is not to scale.
N
S
W E
C B
A
Wind velocity
50 km·hr−^1
