Answer:
the correct option is C
Explanation:
The intensity of a lamp depends on the power of the lamp that is provided by the current flowing over it, therefore the intensity would increase if we raise the current.
Another way to increase the intensity is to decrease the area with a focusing lens, as the intensity is power over area, decreasing the area increases the power.
When we see the possibilities we see that the correct option is C
Answer:
a) W₁ = - 127 J, b) W₂ = 148.18 J, c) = 3.43 m/s and d) = 3.43 m / s
Explanation:
The work is given the equation
W = F. d
Where the bold indicates vectors, we can also write this expression take the module of each element and the angle between them
W = F d cos θ
They give us displacement, let's use Newton's second law to find strength, like the block has an equal acceleration (a = g / 7). We take a positive sign down as indicated
W-T = m a
T = W -m a
T = mg -mg/7
T = mg 6/7
T = 3.6 9.8 6/7
T = 30.24 N
Now we can apply the work equation to our problem
a) the force of the cord is directed upwards, the displacement is downwards, so there is a 180º angle between the two
W₁ = F d cos θ
W₁ = 30.24 4.2 cos 180
W₁ = - 127 J
b) the force of gravity is directed downwards and the displacement is directed downwards, the angle between the two is zero (T = 0º)
W₂ = (mg) d cos 0º
W₂ = 3.6 9.8 4.2
W₂ = 148.18 J
c) kinetic energy
K = ½ m v²
Let's calculate speed with kinematics
² = vo² + 2 a y
v₀ = 0
a = g / 7
² = 2g / 7 y
= √ (2 9.8 4.2 / 7)
= 3.43 m/s
We calculate
K = ½ 3.6 3.43²
K = 21.18 J
d) the speed of the block and we calculate it in the previous part
= 3.43 m / s
Answer:
x = 0.68 meters
Explanation:
It is given that,
Mass of the car, m = 1500 kg
Speed of the car, v = 25 m/s
Spring constant of the spring,
When the car hits the uncompressed horizontal ideal spring the kinetic energy of the car is converted to the potential energy of the spring. Let x is the maximum distance compressed by the spring such that,
x = 0.68 meters
So, the spring is compressed by a distance of 0.68 meters. Hence, this is the required solution.
The maximum distance the spring compresses when a 1500 kg car moving at 25 m/s hits it, given a spring constant of 2.0 × 10⁶N/m, is approximately 0.53 meters or 53 centimeters.
In this specific problem, we can apply the conservation of energy principle, where the initial kinetic energy of the car is converted into potential energy stored in the spring when the car comes to a stop. The formula for kinetic energy is K = 1/2 × m× v² and for potential energy stored in a spring is U = 1/2×k × x², where m = mass of the car, v = velocity of the car, k = spring constant, and x = maximum distance the spring is compressed.
By setting the kinetic energy equal to potential energy (since no energy is lost), we get 1/2 × m×v² = 1/2×k×x². Solving this equation for x (maximum compression of the spring), we obtain x = sqrt((m×v²)/k). Substituting the given values, x = sqrt((1500 kg× (25 m/s)²) / (2.0 × 10⁶ N/m)), which yields approximately 0.53 meters or 53 centimeters. Therefore, the maximum distance the spring compresses is 53 cm.
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Answer:
(A). The time is 5.47 sec.
(B). The speed of the rock just before it strikes the ground is 39.59 m/s.
Explanation:
Given that,
Initial velocity = 14.0 m/s
Height = 70.0 m
(A). We need to calculate the time
Using second equation of motion
Put the value into the formula
(B). We need to calculate the speed of the rock just before it strikes the ground
Using third equation of motion
Put the value into the formula
Hence, (A). The time is 5.47 sec.
(B). The speed of the rock just before it strikes the ground is 39.59 m/s.
d1=_____m
Part B:
d2=______m
Answer:
Explanation:
In projectile motion , range of projectile is given by the expressions
R = u²sin2θ / g
where u is velocity of projectile.
u = 27 m/s θ = 50
12 = 27² sin 2θ / 9.8
sin 2θ = .16
θ = 9.2 / 2
= 4.6
When we place 90- θ in place of θ , in the formula of range , we get the same value of projectile. hence at 85.4 ° , the range will be same.
Answer:
The reflection of light can be roughly categorized into two types of reflection: specular reflection is defined as light reflected from a smooth surface at a definite angle, and diffuse reflection, which is produced by rough surfaces that tend to reflect light in all directions
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Explanation:
Reflection is the process of light bouncing off a surface and changing its direction. There are two types of reflection: specular reflection and diffuse reflection.
Reflection is the process of light bouncing off a surface and changing its direction. There are two types of reflection: specular reflection and diffuse reflection.
Specular reflection occurs when light reflects off a smooth surface, such as a mirror, at a specific angle.
Diffuse reflection occurs when light reflects off a rough surface, such as paper or clothing, and scatters in many different directions.
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Answer: i think you should place it on the red line
Explanation:
hope this helps
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