Answer:
a) 45 s , b) vₐ = 90 m / s, v_b = 162 m / s, c) x_b = 3.328 10⁴ m
Explanation:
We can solve this exercise using the kinematic relations
Vehicle A
xₐ = v₀ₐ t + ½ aₐ t²
vehicle B
starts two seconds later
x_b = v_{ob} (t-2) + ½ a_b (t-2) ²
as cars start from rest their initial velocities are zero
at the point where they meet, the position must be the same for both vehicles
xa = 0 + ½ aₐ t²
xb = 0 + ½ a_b (t-2) ²
½ aₐ t² = ½ a_b (t-2) ²
t = (t-2)
t (1 - \sqrt{ \frac{a_a}{a_b} }) = 2
t (1 - ⅔, ) = 2
t = 2 / 0.4444
t = 45 s
b)
the speed of each car
vₐ = voa + aa t
vₐ = 0 + 2 45
vₐ = 90 m / s
v_b = 3.6 45
v_b = 162 m / s
c) xb = 0 + ½ ab (t-2) ²
x_b = ½ 3.6 (45-2) ²
x_b = 3.328 10⁴ m
Answer:
Option D.
Explanation:
The correct answer is Option D.
The shrinkage of the bridge material is because of thermal contraction.
Thermal contraction and thermal expansion are the phenomena of the bridge material which takes place due to the change in temperature of the atmosphere.
When the temperature of the surrounding increases expansion of the bridge material takes place and when temperature decreases the contraction of the material takes place.
This phenomenon sometimes damages the structure because due to continuous expansion and contraction of materials strength of the bridge decreases.
Answer:
To check whether a chemical equation is balanced or not we usually look if elements on the product side are numerically equal to the reactant side or not.
A. Na + MgCl₂ → NaCl + Mg
<em> Reactant Product</em>
Na = 1 1
Mg = 1 1
Cl = 2 1
<u>Unb</u><u>alanced </u>
B. 2LiOH + H₂S → Li₂S + 2H₂O
<em>Reactant Product</em>
Li = 2 2
S = 1 1
O = 2 2
H = 4 4
<u>Balanced</u>
C. AgNO₃ + NaCl → NaNO₃ + AgCl
<em>Reactant Product</em>
Ag = 1 1
N = 1 1
Na = 1 1
Cl = 1 1
O = 3 3
<u>Balanced</u>
D. 3PBr₃ + 2Cl₂ → 3PCl₃ + 2Br₂
<em>Reactant Product</em>
P = 3 3
Br = 9 4
Cl = 4 9
<u>Unbalanced</u>
Therefore, equations B and C are balanced chemical equations.
Answer:
Mass = Size, Weight = Heaviness
Explanation:
Mass is how much matter that is in an object
Weight is a measurement that indicates how heavy something
Answer: Because of Inertia
Explanation: According to Newton first law, that a body in a linear motion will continue to be in motion except an external for act on it
But also, a body in motion will always like to continue in motion and have a reluctance tendency to stop because of inertia.
the crash test dummies' bodies will continue to move forward even though the car stopped because of inertia.