Answer:
y = 2.74 m
Explanation:
The linear thermal expansion processes are described by the expression
ΔL = α L ΔT
Where α the thermal dilation constant for concrete is 12 10⁻⁶ºC⁻¹, ΔL is the length variation and ΔT the temperature variation in this case 20ªc
If the bridge is 250 m long and is covered by two sections each of them must be L = 125 m, let's calculate the variation in length
ΔL = 12 10⁻⁶ 125 20
ΔL = 3.0 10⁻² m
Let's use trigonometry to find the height
The hypotenuse Lf = 125 + 0.03 = 125.03 m
Adjacent leg L₀ = 125 m
cos θ = L₀ / Lf
θ = cos⁻¹ (L₀ / Lf)
θ = cos⁻¹ (125 / 125.03)
θ = 1,255º
We calculate the height
tan 1,255 = y / x
y = x tan 1,255
y = 125 tan 1,255
y = 2.74 m
<u>Answer:</u> The velocity of the 2.2 kg block is 5.23 m/s
<u>Explanation:</u>
To calculate the velocity of the 2.2 kg block after the collision, we use the equation of law of conservation of momentum, which is:
![m_1u_1+m_2u_2=m_1v_1+m_2v_2](https://tex.z-dn.net/?f=m_1u_1%2Bm_2u_2%3Dm_1v_1%2Bm_2v_2)
where,
= mass of block 1 = 5 kg
= Initial velocity of block 1 = 2.3 m/s
= Final velocity of block 1 = 0 m/s
= mass of block 2 = 2.2 kg
= Initial velocity of block 2 = 0 m/s
= Final velocity of block 2 = ?
Putting values in above equation, we get:
![(5\times 2.3)+(2.2\times 0)=(5.0\times 0)+(2.2\times v_2)\\\\v_2=\frac{(5\times 2.3)}{2.2}=5.23m/s](https://tex.z-dn.net/?f=%285%5Ctimes%202.3%29%2B%282.2%5Ctimes%200%29%3D%285.0%5Ctimes%200%29%2B%282.2%5Ctimes%20v_2%29%5C%5C%5C%5Cv_2%3D%5Cfrac%7B%285%5Ctimes%202.3%29%7D%7B2.2%7D%3D5.23m%2Fs)
Hence, the velocity of the 2.2 kg block is 5.23 m/s
d = distance traveled by her on her bicycle on a long flat road = 24 kilometer
t = time taken by her to travel distance "d" on her bicycle on a long flat road = 1.2 hours
v = average speed of vivian = ?
we know that average speed is given as
v = d/t
inserting the values in the above formula
v = 24 kilometer / 1.2 hour
v = 20 kilometer/hour
hence the correct choice is
C) 20 km/h