<span>(a) How fast is it moving when it reaches 12.0 m?
To determine the velocity as it reaches 12.0 m, we use one of the kinematic equations,
</span>V^2 = Vo^2 + 2gh
<span>where Vo = 20 m/s. </span>
<span> g = -9.8 m/s^2 </span>
<span> h = 12.0 m. </span>
V^2 = 20^2 + 2(-9.8)(12.0)
<span>V^2 = 164.8
V = 12.84 m/s
(b) How long is required to reach this height?
To determine the maximum height, we use the same equation we used above,
</span>V^2 = Vo^2 + 2gh
where Vo = 20 m/s.
g = -9.8 m/s^2
V = 0 (since at the maximum height velocity is zero)
0^2 = 20^2 + 2(-9.8)h
<span>h = 20.41 m
(c) Why are there two answers for (b)?
There are two answers for b because it would travel a distance up and travel a distance down.</span>
Answer:
<h2>
187,500N/m</h2>
Explanation:
From the question, the kinectic energy of the train will be equal to the energy stored in the spring.
Kinetic energy = 1/2 mv² and energy stored in a spring E = 1/2 ke².
Equating both we will have;
1/2 mv² = 1/2ke²
mv² = ke²
m is the mass of the train
v is the velocity of then train
k is the spring constant
e is the extension caused by the spring.
Given m = 30000kg, v = 4 m/s, e = 4 - 2.4 = 1.6m
Substituting this values into the formula will give;
30000*4² = k*1.6²

The value of the spring constant is 187,500N/m
Answer:
F = 313.6 N
Explanation:
weight is the force acting on an object due to gravity.
so,
- f = ma (m = mass, a = acceleration)
- f = 32 × 9.8
- f = 313.6 Newton
( note : i have taken acceleration due to gravity as 9.8, it can be taken as an approx of 10, so if you have to take 10, the weight of girl will be 320 Newton )
<em>i</em><em> </em><em>hope</em><em> </em><em>it</em><em> </em><em>helped</em><em>.</em><em>.</em><em>.</em><em>.</em>
The relationship between the speed, the frequency and the wavelength of a wave is given by:

where
f is the frequency
v is the speed of the wave

is its wavelength
for the pressure wave in this problem,

and v=1400 m/s, therefore its frequency is
Answer:
53.5 N
Explanation:
Vertical component of the F force 50 sin30 = 25 N upward
force of gravity = m g = 8 * 9.81 =78.5 N Downward
NET downward force by block on table = net upward force exerted by table = 78.5 -25 =53.5 N