Page 82 - Physics

Physics for Secondary Schools
on the moon is one-sixth that of
the earth?
5. Two students are pushing the
wooden block laid on the table with
forces as shown in Figure 3.23.
F = 35 N F = 30 N
1 2
Figure 3.23
(a) Will the wooden block move?
Which direction will the block
move?
(b) How much extra force is acting
on the object if the object is not
moving due to the application of
these two forces?
6. (a) Distinguish between the forces
of attraction and forces of
repulsion.
(b) Figure 3.24 shows part of a toy
which contains two ring-shaped,
permanent magnets. A plastic
rod passes through the centre
of both magnets.
10. A person pulls a cart with a force
(a) (b)
Figure 3.24
The top magnet can move up and
down freely around the plastic rod. The
magnetic poles on the bottom magnet
are shown in Figure 3.24.
(i) The top magnet fl oats in the air
above the bottom magnet. On
76
Physics Form 1 Final.indd 76
Figure 3.24 (a), mark the poles
on the top magnet and explain
why it fl oats in the air above the
bottom magnet.
(ii) The top magnet is replaced with
a ring made of iron as shown in
Figure 3.24 (b). Explain why the
iron ring sticks to the bottom
magnet.
7. In each statement, suggest the type
of force that comes into play.
(a) You placed two bar magnets
close to each other, and they
pushed each other away.
(b) You exerted a force on a book
to move it across a table, but it
eventually comes to a stop.
(c) If you drop a ball from a height,
what force pulls it down towards
the ground?
8. You want to lift a heavy box. The
force of gravity pulls it downwards
with 500 N.
(a) How much force will you have
to apply to lift the box?
(b) If your friend supports the box
from below with a force of
270 N, how much force will you
have to apply to lift the box?
9. Why car dashboards are fi xed with
air bags?
1500 N.
(a) Will the cart move if the force
of friction between the cart and
the ground is 2000 N? why?
(b) Will the cart move if the force
of friction between the cart and
the ground is 1000 N? why?
Student’s Book Form One
16/10/2024 20:56