Page 154 - Physics

Physics for Secondary Schools

Example 7.5 Solution

The pistons of a hydraulic press have their areas (a) Force applied on
given as 0.0003 m and 0.02 m , respectively. piston 1
2
2
If the small piston is pushed down with a force
of 120 N, what is the force on the large piston? P = P 2
1
Solution; F 1 = F 2
F A 1 A 2
F = 1 A 2
2
A 1 F = F 2 × A
0.02 m 2 1 A 2 1
F = ×120 N
2
0.003 m 2 5 000 N
F = 2 × 0.02 m 2
∴ F = 8 000 N
1
2 0.10 m
Therefore, force on the large piston is 8 000 N.
5 000 N
2
F = 2 × 0⋅02 m = 1 000 N
1
0⋅10 m

Example 7.6
Therefore, force on piston 1
A hydraulic press has pistons with areas of is 1 000 N.
0.02 m and 0.1 m as shown in Figure 7.19. A
2
2
car weighing 5 000 N sits on a platform mounted (b) Distance moved by
on the larger piston. Piston 1

(a) How much force must be applied to piston 1 d A
to lift the car? d 1 = A 2

(b) How far must piston 1 be pushed downward 2 1
to raise the car 0.3 m? d = A 2 × d
1 A 2
1
0.10 m 2
d = × 0.3 m
1 0.02 m 2
Piston 2

d =? 0⋅10 m 2
d =
Piston 1 1 A = 0.10 m 2 2 × 0⋅3 m = 1.5 m
0⋅02 m
1
2
A = 0.02 m 2
1
Therefore, distance moved
by piston 1 is 1.5 m.
Figure 7.19

148
Student’s Book Form One

Physics Form 1 Final.indd 148 16/10/2024 20:57