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3 years ago

The largest aperture telescopes are reflectors because they require a _____ focal length.

1 answer:

5 0

The largest aperture telescopes are reflectors because they require a shorter focal length. I think that is the answer! I hope that it helps!

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Driving safely at night requires seeing well not only in low light conditions, but also being able to see low contrast

Monica [59]

Answer:

True

Explanation:

Driving safely at night requires seeing well not only under low light, but also requires drivers to see low-contrast objects.

8 0

1 year ago

A city planner is working on the redesign of a hilly portion of a city. An important consideration is how steep the roads can be

Artyom0805 [142]

Explanation:

It is known that relation between force and acceleration is as follows.

F = $m \times a$

I is given that, mass is 1090 kg and acceleration is 21 m/s. Therefore, we will calculate force as follows.

F = $m \times a$

= $1090 \times (\frac{21}{16})$

= 1430.625 N

Also, it is known that

$sin(\theta) = \frac{\text{Force car can exert}}{\text{Force gravity pulls car}}$

$sin(\theta) = \frac{1430.625 N}{(1090 \times 9.8) N}$

$\theta$ = 7.70 degrees

Thus, we can conclude that the maximum steepness for the car to still be able to accelerate is 7.70 degrees.

8 0

3 years ago

A wheel free to rotate about its axis that is not frictionless is initially at rest. A constant external torque of +46 N·m is ap

Rom4ik [11]

Answer:

Explanation:

Let Torque due to friction be

Net torque

= 46 - F

Angular impulse = change in angular momentum

=( 46 - F ) x 17 = I X 580

When external torque is removed , only friction creates torque reducing its speed to zero in 120 s so

Angular impulse = change in angular momentum

F x 120 = I X 580

( 46 - F ) x 17 = F x 120

137 F = 46 x 17

F = 5.7 Nm

b )

Putting this value in first equation

5.7 x 120 = I x 580

I = 1.18 kg m²

8 0

3 years ago

Calculate the potential energy of a 4 kg cat crouched 3 meters off the ground

Tom [10]

Gravitational potential energy = mass × gravity × height

Ep = (4)(9.81)(3)

Energy = 117.72 Joules

= 1.2x10^2 Joules

7 0

3 years ago

Read 2 more answers

A mass m is tied to an ideal spring with force constant k and rests on a frictionless surface. The mass moves along the x axis.

7nadin3 [17]

Answer: $x=\frac{x_m}{\sqrt{2}}$

Explanation:

Given

initially mass is stretched to $x_m$

Let k be the spring Constant of spring

Therefore Total Mechanical Energy is $\frac{kx_m^2}{2}$

Position at which kinetic Energy is equal to Elastic Potential Energy

$K=\frac{mv^2}{2}$

$U=\frac{kx^2}{2}$

it is given

$k=U$

thus $2U=\frac{kx_m^2}{2}$

$2\times \frac{kx^2}{2}=\frac{kx_m^2}{2}$

$2x^2=x_m^2$

$x=\frac{x_m}{\sqrt{2}}$

3 0

4 years ago