Diagram 4.1
shows a newborn baby sleeping in a cradle which is suspended by a spring P.
|
(a)
|
What is meant by the elastic
limit of a spring?
Maximum
force that can be applied to a spring such that the spring will still be
elastic/ return to its original length when the force is removed.
…………………………………………………………………………….
…………………………………………………………………………….
[1 mark]
|
|||
|
(b)
|
When an older baby wants to sleep
in the cradle, the elastic limit of spring P will be exceeded. Hence an
additional spring has to be added or spring P has to be replaced.
|
|
|
|
(iii)
|
Give one reason
for your answer in (b)(i)
Parallel
arrangement is less elastic/more stiff // k is higher.
…………………………………………………………………
[1 mark]
|
|
|
(c)
|
State two types
of springs which can be used to replace spring P.
Spring
with thicker wire // smaller spring diameter //shorter length// larger force
constant
………………………………………………………………………….
………………………………………………………………………….
[2 marks]
|
|
|
|
(d)
|
A spring has an original length of
30 cm. When a load of mass 400 g is placed on it, the spring is compressed to
22 cm. Calculate the mass of load required to compress the spring to 16 cm
1.
8 cm ------ 400 g
1 cm ------50 g //
force constant = 50 g cm-1
2. 14 cm ----- 14 x 50
= 700 g
[3
marks]
|
|