Answer:
a. 30 N / m
b. 9.0 N
Explanation:
Given that
Unstretched length of the spring,
= 20.0cm = 0.2m
a) When the mass of 4.5N is hanging from the second spring, then extended length Is
= 35.0cm = 0.35m
So, the change in spring length when mass hangs is

= (0.35 - 0.20) m
= 0.15m
As spring are identical
Let us assume that the spring constant be "k", so at equilibrium
Restoring Force on spring = Block weightage
kx = W = 4.50

= 30 N / m
b) Now for the third spring, stretched the length of spring is
= 50cm = 0.5m
So, the change in spring length is

= (0.5-0.20)m
= 0.30m
At equilibrium,
Restoring Force on spring = Block weightage
Now using all mentioned and computed values in above,

= 30(0.3)
= 9.0 N
Answer: C.
Explanation:
i choose B and got it wrong it told me the answer after on edge.
Answer:
(a) 62.5 m
(b) 7.14 s
Explanation:
initial speed, u = 35 m/s
g = 9.8 m/s^2
(a) Let the rocket raises upto height h and at maximum height the speed is zero.
Use third equation of motion


h = 62.5 m
Thus, the rocket goes upto a height of 62.5 m.
(b) Let the rocket takes time t to reach to maximum height.
By use of first equation of motion
v = u + at
0 = 35 - 9.8 t
t = 3.57 s
The total time spent by the rocket in air = 2 t = 2 x 3.57 = 7.14 second.
Answer:
A
Explanation:
voltage between A and C is equal battery's voltage.
The velocity of the aircraft relative to the ground is 240 km/h North
Explanation:
We can solve this problem by using vector addition. In fact, the velocity of the aircraft relative to the ground is the (vector) sum between the velocity of the aircraft relative to the air and the velocity of the air relative to the ground.
Mathematically:

where
v' is the velocity of the aircraft relative to the ground
v is the velocity of the aircraft relative to the air
is the velocity of the air relative to the ground.
Taking north as positive direction, we have:
v = +320 km/h
(since the air is moving from North)
Therefore, we find
(north)
Learn more about vector addition:
brainly.com/question/4945130
brainly.com/question/5892298
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