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makkiz [27]
4 years ago
7

You do a certain amount of work on an object initially at rest, and all the work goes into increasing the object’s speed. If you

do work WITH, suppose the object’s final speed is v. What will be the object’s final speed if you do twice as much work?1. 4 v2. 2 v3. still v4. v/25. v.2
Physics
1 answer:
mezya [45]4 years ago
7 0

Answer:

v_{f2} = √ 2 v_{f}

Explanation:

Work and kinetic energy are related by

       W = ΔK

The formula for work is

    W = F . d

The formula for kinetic energy is

      K = ½ m v²

     W = K_{f} - K₀

Since the body starts from rest, the initial velocity is ro and therefore the kinetic energy is zero.

       W = K_{f}

       W = ½ m v_{f}²

       v_{f} = √ 2W / m

       

    If  W = 2 W₀

       v_{f2} = √ 2 (2W₀) / m

       v_{f2} = √ 2  √2W₀ / m

       v_{f2} = √ 2 v_{f}

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A car with a total mass of 1800 kg (including passengers) is driving down a washboard road with bumps spaced 4.9 m apart. The ri
Drupady [299]

Answer:

k = 9.6 x 10^5 N/m or 9.6 kN/m

Explanation:

First, we need to use the expression to calculate the spring constant which is:

w² = k/m

Solving for k:

k = w²*m

To get the angular velocity:

w = 2πf

The problem is giving the linear velocity of the car which is 5.7 m/s. With this we can calculate the frequency of the car:

f = V/x

f = 5.7 / 4.9 = 1.16 Hz

Now the angular velocity:

w = 2π*1.16

w = 7.29 rad/s

Finally, solving for k:

k = (7.29)² * 1800

k = 95,659.38 N/m

In two significant figures it'll ve 9.6 kN/m

5 0
3 years ago
Read 2 more answers
. Maria walked 1.5 miles south to her house in 0.5 hours. What is her speed in miles per hour?
Simora [160]

1) 3 miles/Hour

The speed is defined as the distance covered divided by the time taken:

v=\frac{d}{t}

where

d = 1.5 mi is the distance

t = 0.5 h is the time taken

Substituting,

v=\frac{1.5}{0.5}=3 mi/h

2) 1.34 m/s south

Velocity, instead, is a vector, so it has both a magnitude and a direction. We have:

d=1.5 mi \cdot 1609 m/mi = 2414 m is the displacement in meters

t=0.5 h \cdot 3600 s/h =1800 s is the time taken in seconds

Substituting,

v=\frac{2414 m}{1800 s}=1.34 m/s

And the direction of the velocity is the same as the displacement, so it is south.

6 0
4 years ago
What is the primary difference between an ideal emf device and a real emf device?.
EleoNora [17]

Answer:

A real emf device has an internal resistance, but an ideal emf device does not.

3 0
2 years ago
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two forces x and y are acting at 120 degrees to each other, if the magnitude are 8N and 10N respectively determine their resulta
Ber [7]

The resultant force of both forces is 15.62 N.

<h3 /><h3>What is resultant?</h3>

The Resultant of forces is a single force obtained when two or more forces are combined.

To calculate the resultant of the force, we use the formula below.

Formula:

  • R = √[a²+b²-2abcos∅]..................... Equation 1

Where:

  • R = Resultant of the forces.
  • ∅ = Angle between both forces

From the question,

Given:

  • a = 8 N
  • b = 10 N

Substitute these values into equation 1

  • R = √[8²+10²-2×8×10cos120°]
  • R = √[64+100-160cos120°]
  • R =√ [164-160(-0.5)]
  • R = √[164+80]
  • R = √(244)
  • R = 15.62 N

Hence, the resultant force of both forces is 15.62 N.

Learn more about resultant force here: brainly.com/question/25239010

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8 0
2 years ago
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A wave pulse traveling to the right along a thin cord reaches a discontinuity where the rope becomes thicker and heavier. What i
Tema [17]

Answer:

b) the reflected pulse returns inverted while the transmitted pulse is right side up

Explanation:

A wave pulse traveling to the right along a thin cord reaches a discontinuity where the rope becomes thicker and heavier.

Then, as far as orientation of reflected and transmitted pulses are concerned the reflected pulse returns inverted while the transmitted pulse is right side up.

Hence the correct answer is b.

5 0
3 years ago
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