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3 years ago

The crankshaft in a race car goes from rest to 3000 rpm in 3.0 s . (a) What is the crankshaft's angular acceleration?

Physics

1 answer:

Talja [164]3 years ago

7 0

Answer:

75 rotations

Explanation:

f0 = 0, f = 3000 rpm = 50 rps, t = 3 s

(a) use first equation of motion for rotational motion

w = w0 + α t

2 x 3.14 x 50 = 0 + α x 3

α = 104.67 rad/s^2

(b) Let θ be the angular displacement

use second equation of motion for rotational motion

θ = w0 t + 1/2 α t^2

θ = 0 + 0.5 x 104.67 x 3 x 3

θ = 471.015 rad

The angle turn in one rotation is 2 π radian.

Number of rotation = 471.015 / (2 x 3.14) = 75 rotations

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3 years ago

In the graph, which region shows nonuniform positive acceleration?

cricket20 [7]

Answer: A.AB

Explanation:

This Velocity vs Time graph shows the acceleration of a body or object, since acceleration is the variation of velocity in time.

As we can see in the attached image, the graph can be divided in four segments:

OA: In this segment the acceleration is changing at a uniform rate. In addition we can see it has a positive slope, hence we are dealing with a positive uniform acceleration.

AB: In this segment the acceleration is changing at a nonuniform rate, since in this part it is not possible to calculate the slope. However if this were uniform, the slope woul be positive. This means the <u>acceleration is nonuniform and positive.</u>

BC: In this segment the acceleration is changing at a nonuniform rate, since in this part it is not possible to calculate the slope. However if this were uniform, the slope woul be negative. This means the acceleration is nonuniform and negative.

CD: In this segment the acceleration is changing at a uniform rate. In addition we can see it has a negative slope, hence we are dealing with a negative uniform acceleration.

From all these segments, the only one that fulfils the nonuniform positive acceleration condition is option A:

Segment AB

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3 years ago

Read 2 more answers

Please help answer both of these !! I’m in a rush :(((

Leno4ka [110]

Answer: search it on browser

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3 years ago

You want to get a Q-taco from stripes so you head 3 miles at 45 degrees S of E. What

Cloud [144]

Trigonometry allows finding the result for the decomposition of the displacement vector is:

x = 2.12 mi

y = -2.12 mi

Displacement is a vector quantity, which has modulus and direction.

The cardinal points are a reference system with respect to which measurements are made, this system is related to the Cartesian system with the East in the positive direction of the x-axis and the North with the positive direction of the y-axis.

In the attached we can see a diagram of the vector and its components, the indicated direction of 45 S of the E, in the Cartesian system where the angles are measured from the positive side of the x-axis in a counterclockwise direction is:

θ = 360 - 45

θ = 315º

Let's use trigonometry to decompose the vector d = 3 mi

cos 315 = $\frac{x}{d}$

sin 315 = $\frac{y}{d}$

x = d cos 315

y = d sin 315

Let's calculate

x = 3 cos 315

y = 3 sin 315

x = 2.12 mi

y = -2.12 mi

The negative sign indicates that the displacement is towards the negative side, that is, towards the South.

In conclusion using trigonometry we can find the result for the decomposition of the displacement vector are:

x = 2.12 mi

y = -2.12 mi

Learn more here: brainly.com/question/1666179

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3 years ago

A block slides down a frictionless inclined ramp. If the ramp angle is 17.0° and its length is find the speed of the block as it

SashulF [63]

Answer:

$2.4\sqrt{L}$ where L is the length of the ramp

Explanation:

Let L (m) be the length of the ramp, and g = 9.81 m/s2 be the gravitational acceleration acting downward. This g vector can be split into 2 components: parallel and perpendicular to the ramp.

The parallel component would have a magnitude of

$gsin\theta = 9.81 sin17^o = 2.87 m/s^2$

We can use the following equation of motion to find out the final velocity of the book after sliding L m:

$v^2 - v_0^2 = 2a\Delta s$

where v m/s is the final velocity, $v_0$ = 0m/s is the initial velocity when it starts from rest, a = 2.87 m/s2 is the acceleration, and $\Delta s = L$ is the distance traveled:

$v^2 - 0 = 2*2.87*L$

$v = \sqrt{5.74L} = 2.4\sqrt{L}$

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3 years ago