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3 years ago

HELP!! ME pls which Which of the following graphs correctly shows the relationship between KE and VELOCITY? *

Physics

1 answer:

faltersainse [42]3 years ago

3 0

Answer: Option 3.

Explanation:

Formula for kinetic energy is

K.E = (1 / 2) * (m * v ^ 2)

Assuming mass to be constant,

We can see that K.E is proportional to v^2.

It means that when you substitute the value of velocity in v, kinetic energy increases with v^2.

Option 1 and 2 are eliminated because the relationship between kinetic energy and velocity in the graph is shown as linear. We already know from formula that the relationship is not linear.

Option 4 is incorrect because kinetic energy must be zero when velocity is zero. This graph shows kinetic energy is becoming infinite as velocity tends to 0.

So option 3 is correct answer.

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The lawn sprinkler consists of four arms that rotate in the horizontal plane. The diameter of each nozzle is 8 mm, and the water

sashaice [31]

Answer: the constant angular velocity of the arms is 86.1883 rad/sec

Explanation:

First we calculate the linear velocity of the single sprinkler;

Area of the nozzle = π/4 × d²

given that d = 8mm = 8 × 10⁻³

Area of the nozzle = π/4 × (8 × 10⁻³)²

A = 5.024 × 10⁻⁵ m²

Now total discharge is dived into 4 jets so discharge for single jet will be;

Q_single = Q / n = 0.006 / 4 = 1.5 × 10⁻³ m³/sec

So using continuity equation ;

Q_single = A × V_single

V_single = Q_single/A

we substitute

V_single = (1.5 × 10⁻³) / (5.024 × 10⁻⁵)

V_single = 29.8566 m/s

Now resolving the forces as shown in the second image,

Vt = Vcos30°

Vt = 29.8566 × cos30°

Vt = 25.8565 m/s

Finally we calculate the angular velocity;

Vt = rω

ω_single = Vt / r

from the given diagram, radius is 300mm = 0.3m

so we substitute

ω_single = 25.8565 / 0.3

ω_single = 86.1883 rad/sec

Therefore the constant angular velocity of the arms is 86.1883 rad/sec

7 0

3 years ago

Write the equation expressing the relationship "y varies directly as x." use k as the constant of proportionality.

Alexeev081 [22]

The equation expressing the statement "y varies directly as x" is $y=kx.$

Explanation

The statement that $y$ varies directly as $x$ is analogous to saying that the ratio of $y$ to $x$ is constant. In other words, when $x$ increases, $y$ likewise increases and that when $x$ decreases, $y$ decreases proportionally.

Mathematically, we express the relationship that the ration of $y$ is to $x$ is constant is expressed as; $\frac{y}{x} =k$ where $k$ is the constant of proportionality.