Answers
Answer:
1. (a) The final velocity is 20 m/s
(b) The distance travelled is20 meters
2. The distance travelled by the train in the 30 seconds is 825 meters
3. The most correct option is;
(d) 53 km
4. The heat, developed by the electric iron is 15,000 joules
5. a) In the first network the resistance between A and B is 2 Ω
b) In the second network the resistance between A and B is 4Ω
c) In the third network the resistance between A and B is 6Ω
d) In the fourth network the resistance between A and B is 2Ω
Explanation:
1. (a) The parameters of the cheetahs motion are;
The initial motion (velocity) of the cheetah = 0 m/s (The cheetah starts from rest)
The acceleration of the cheetah, a = 2 m/s²
The duration of the acceleration of the cheetah, t = 10 seconds
The kinematic equation of the motion of uniform acceleration, of the cheetah can be written in the following form;
v = u + a·t
s = u·t + 1/2·a·t²
Where;
v = The final velocity
u = The initial velocity = 0 m/s
a = The acceleration of the cheetah = 2 m/s²
s = The distance traveled
∴ v = 0 + 2 × 10 = 20
The final velocity, v = 20 m/s
(b) From s = u·t + 1/2·a·t², we have;
s = 0 × 10 + 1/2 × 10 × 2² = 20
The distance travelled, s = 20 meters
2. The given details of the motion of the train are;
The initial velocity of the train, u = 20 m·s⁻¹
The acceleration of the train, a = 0.5 m·s⁻²
The duration of the train's acceleration, t = 30 seconds
Therefore, the distance travelled, 's', is given by; s = u·t + 1/2·a·t²
∴ s = 20 × 30 + (1/2) × 0.5 × 30² = 825
The distance travelled by the train in the 30 seconds, s = 825 meters
3. The given distance the truck covers with the average speed of 80 km/h, d₁ = 40 km
The distance the truck then covers with the average speed of 40 km/h, d₂ = 40 km
[tex]Average \ speed = \dfrac{Total \ distance}{Time}[/tex]
[tex]\therefore time, \, t = \dfrac{Total \ distance}{Average \ speed}[/tex]
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(80 km·h) t₁ = 0.5 hour
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(40 km·h) t₂ = 1 hour
The total time taken to cover both 40 km distances, t = t₁ + t₂
∴ The total time taken to cover both 40 km distances, t = (0.5 + 1) hour = 1.5 hours
The total distance covered at both speeds, d = d₁ + d₂
∴ d = 40 km + 40 km = 80 km
The average speed of the truck for the total distance, [tex]v_{average}[/tex] = d/t
∴ [tex]v_{average}[/tex] = 80 km/1.5 hours = 53.[tex]\overline 3[/tex] km/h ≈ 53 km/h
The average speed of the truck for the total distance, [tex]v_{average}[/tex] ≈ 53 km/h
The correct option is (d) 53 km
4. The heat, 'H', developed by the electric iron is given by the following formula;
H = I²·R·t
Where;
I = The current flowing in the electric iron = 5 A
R = The resistance of the iron = 20Ω
t = The time duration of the flow of the current = 30 s
∴ H = (5 A)² × 20 Ω × 30 s = 15,000 joules
The heat, developed by the electric iron, H = 15,000 joules
5. Let 'R' represent the resistance between A and B in each network
a) For the first network, we have;
1/R = 1/(2 + 2) + 1/(2 + 2) = 1/4 + 1/4 = 1/2
∴ R = 2 Ω
∴ The resistance between A and B is 2 Ω
b) For the second network, we have;
R = 1/(1/2 + 1/2) + 3 = 4
R = 4Ω
∴ The resistance between A and B is 4 Ω
c) For the third network, we have;
R = 2 + 1/(1/4 + 1/4) + 2 = 6
R = 6Ω
∴ The resistance between A and B is 6 Ω
d) For the fourth network, we have;
R = 1/(1/2 + 1/2) + 1/(1/2 + 1/2) = 2
R = 2Ω
∴ The resistance between A and B is 2 Ω
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Answers
Answer:
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Answers
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Answers
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Answers
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Answers
Answer:
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Answers
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Answers
To answer this question, you need to understand the law of conservation of energy. Essentially, the law states that energy cannot be created or destroyed; it is always conserved.
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Let's start solving for ∆H:
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∆H = [tex]\frac{90}{6*9.80}[/tex]
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Answers
Answer:
Yes, because of the force of gas exploding the volcano from pressure is a force.
GIVING BRAINLIEST PLEASE HELP!!
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Answers
Answer:
B is the answer!!
Explanation:
Give 1 real life example of a scenario that takes advantage of the inverse relationship between force and time when impulse is constant. Describe how it is an example of impulse and how force and time are involved.
Answers
Answer:
On real life example of a scenario that takes advantage of the inverse relationship between force and time when impulse is constant is when making a serve with a lawn tennis racket
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When however, the lawn tennis player moves the racket faster, with the strings of the racket highly tensioned he uses more force and the ball also spends less time on the racket to produce the same momentum
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The impulse of a force, ΔP is given by the following formula;
ΔP = F × Δt
Where ΔP is constant, we have;
F ∝ 1/Δt
Therefore, for the same impulse, when the force is increased, the time of contact is decreases and vice versa.
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Answers
Answer:
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The average speed of an object is given by the following formula
[tex]Average \ speed = \dfrac{Total \ distance \ covered}{Total \ time \ taken \ to \ cover \ the \ distance}[/tex]
From the graph, we have;
The coordinates of the runner B at the start = (0, 0)
The coordinates of the runner B after 25 seconds = (25, 30)
The total distance covered by the runner B after 25 seconds = The difference between the position at 25 seconds and the origin which is 30 meters
∴ The total distance covered by the runner B after 25 seconds = 30 meters
The time it takes the runner B to cover the distance = The 25 seconds
[tex]\therefore \ For \ the \ runner \ B, the \ average \ speed = \dfrac{30 \ meters}{25 \ seconds} = 1.2 \ m/s[/tex]
The average speed for the runner B for the first 25 seconds = 30 m/(25 s) = 1.2 m/s.
A car travels 9 km East, turns around, then travels 3 km West. What is the car's
DISPLACEMENT? *
Answers
Explanation:
I think you are 100℅ clear.
1.
David is 10% taller than Peter and Peter is 5% shorter than John. It is given that the height of Peter
is 171 cm.
(a) Find the height of John.
Iso
(2 marks)
(b) David claims that he is the tallest person among the three. Do you agree? Explain your answer.
(2 marks)
Answers
Answer:
I don't know if I can help you with that
A 5 kg ball is sitting on top of a hill. It has a Potential Energy of 6000J. What is the height of the ball?
Answers
Explanation:
mass=5 kg
potential energy=6000j
height=?
Now
potential energy =m.g.h
or 6000=5*9.8*h
or 6000=49h
or 6000÷49=h
or h= 122.45m
