Answer: ∆L = 0.49cm ≈ 0.50cm
Therefore there should be 0.5 cm gap between each piece of steel.
Explanation:
Thermal expansion of steel is the increase in size of steel as a result of increased temperature. It can be represented by the mathematical expression:
∆L = L(k)∆T .....1
Where;
∆L is the change in length
L is the initial length
∆T is the change in temperature
k is the specific Linear expansion coefficient.
Given;
L = 12m
∆T = 50°C - 16°C = 34°C
k (for steel) = 1.2 × 10^-6 /C
Substituting the values into the equation 1
∆L = 12 × 34 × 12×10^-6
∆L = 4896 × 10^-6 m
∆L = 0.49cm ≈ 0.50cm
Therefore there should be 0.5 cm gap between each piece of steel.
Answer:
c. 15.4 s
Explanation:
Given the following data;
Mass, m = 50kg
Force, F = 130N
Initial velocity, u = 20m/s
Final velocity, v = 60m/s
To find the time;
First of all, we would solve for acceleration using the formula below;
Force = mass * acceleration
130 = 50*acceleration
Acceleration = 130/50
Acceleration = 2.6m/s²
Now, we would use the first equation of motion to find the time.
V = U + at
60 = 20 + 2.6t
2.6t = 60 - 20
2.6t = 40
t = 40/2.6
Time, t = 15.39 ≈ 15.4 seconds.
26. D. crushing the sugar cube and dissolving it in water.
27. A. atom
28. B. molecule
29. B. plum pudding model of Joseph John Thomson
30. B. He used cathode ray tubes which showed that all atoms contain tiny negatively charged subatomic particles or electrons.
31. D. protons and neutrons are relatively heavier than electrons.
Answer:
average speed is 0.159 m/s
average velocity = 0.0011 m/s
Explanation:
given data
time = 41.6 s
total distance = 6.65 m
length = 0.0463 m
to find out
average speed and the magnitude average velocity
solution
we know average speed formula is
average speed = 
...............1
put here value
average speed = 
average speed is 0.159 m/s
and
average velocity formula is
average velocity = 
...............2
here displacement is initial point to final point and here is 0.0463 m
put here value
average velocity = 
average velocity = 0.0011 m/s
The faster car behind is catching up/closing the gap/gaining on
the slow truck in front at the rate of (90 - 50) = 40 km/hr.
At that rate, it takes (100 m) / (40,000 m/hr) = 1/400 of an hour
to reach the truck.
(1/400 hour) x (3,600 seconds/hour) = 3600/400 = <em>9 seconds</em>, exactly
