1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
krek1111 [17]
3 years ago
14

A child whose weight is 235 N slides down a 4.90 m playground slide that makes an angle of 37.0° with the horizontal. The coeffi

cient of kinetic friction between slide and child is 0.0510. (a) How much energy is transferred to thermal energy? (b) If she starts at the top with a speed of 0.355 m/s, what is her speed at the bottom?
Physics
1 answer:
Basile [38]3 years ago
7 0

Answer:

Explanation:

a) First, let's calculate the value of the Friction force, which is given by the formula:

Ff = u*W

As the Friction force has an X component, it would be:

Ff = u*m*g*cosФ

Where m*g is the weight of the child.

Solving for Ff:

Ff = 0.051 * 235cos37 = 9.57 N

Now, to get the energy transferred to thermal energy (or heat) we need to get the Work done, so:

Wf = Ff * d

Wf = 9.57 * 4.9 = 46.9 J

b) We need to get the downslope component of the child weight, which is:

Wy = 235sin37 = 141.43 N

As you can imagine, the gravity also does work, so:

Wg = Wy * d

Wg = 141.43 * 4.9 = 693 J

Now, let's get the kinetic energy, which can be obtained by this expression:

ΔKe = Wg - Wf

ΔKe = 693 - 46.9 = 646.1 J

The formula for kinetic energy is:

Ke = 1/2 m*V^2

We have the innitial speed which is 0.355 m/s, and the mass can be obtained by m*g so:

Fw= m*g ----> m = Fw/g

m = 235 / 9.8 = 23.97 kg

so the innitial energy is:

Ke = 1/2 * 23.97 * (0.355)^2

Ke = 1.51 J

This could be Ke1, so to get Ke2:

ΔKe = Ke2 - Ke1

Ke2 = Δke + Ke1

Ke2 = 646.1 + 1.51 = 647,61 J

Finally, the speed at the bottom would be:

v = √2Ke/m

v = √2*647.61/23.97

v = 7.35 m/s

You might be interested in
Rony fills a bucket with water and whirls it in a vertical circle to demonstrate that the water will not spill from the bucket a
Romashka-Z-Leto [24]

Answer:

0 N, 3.49 m/s

Explanation:

Draw a free body diagram for the bucket at the top of the swing.  There are two forces acting on the bucket: weight and tension, both downwards.

If we take the sum of the forces in the radial direction, where towards the center is positive:

∑F = ma

W + T = m v² / r

The higher the velocity that Rony swings the bucket, the more tension there will be.  The slowest he can swing it is when the tension is 0.

W = m v² / r

mg = m v² / r

g = v² / r

v = √(gr)

Given that r = 1.24 m:

v = √(9.8 m/s² × 1.24 m)

v = 3.49 m/s

8 0
3 years ago
Babies typically say their first words:
deff fn [24]

Answer:

2nd one if you ask me

almost every baby stats to talk after their a year old

3 0
2 years ago
What happens to an object after being transported to three planets in the solar system?
alukav5142 [94]
The weight changes but the mass will stay the same.
6 0
2 years ago
The energy of a photon of light is __________ proportional to its frequency and __________ proportional to its wavelength.
icang [17]

Answer:

D) directly, inversely

Explanation:

The energy of a photon of light is directly proportional to its frequency and inversely proportional to its wavelength.

Frequency is the number of waves that passes through a point per unit of time.

Wavelength is the is the distance between successive crests or troughs on a wave.

 Mathematically, frequency is related to wavelength and velocity using;

             Energy   =  h x f

                      where h is the Planck's constant

                                  f is the frequency

         

                   Since c  = f ∧

where f is the frequency of the wave

           ∧ is the wavelength of the wave

           c is the speed of light

So;

                 f  = c/∧

  Therefore;

                E  = \frac{h c}{wavelength}

From the equation, we see an inverse relationship between E and wavelength and a direct one with frequency.

           

6 0
3 years ago
A horizontal uniform bar of mass 2.7 kg and length 3.0 m is hung horizontally on two vertical strings. String 1 is attached to t
Jlenok [28]

Answer:

14.36 N

Explanation:

T_{1} = Tension in string 1

T_{2} = Tension in string 2

m_b = mass of the bar = 2.7 kg

W_b = weight of the bar

weight of the bar is given as

W_b = m_{b} g = (2.7) (9.8) = 26.46N

m_m = mass of the bar = 1.35 kg

W_m = weight of the monkey

weight of the monkey is given as

W_m = m_{m} g = (1.35) (9.8) = 13.23N

Using equilibrium of torque about left end

W_{m} (AB) + W_{b} (AB) = T_{2} (AC)\\W_{m} (AB) + W_{b} (AB) = T_{2} (AD - CD)\\(13.23) (1.5) + (26.46)(1.5) = T_{2} (3 - 0.65)\\\\T_{2} = 25.33 N

Using equilibrium of force in vertical direction

T_{1} + T_{2} = W_{b} + W_{m}\\T_{1} + 25.33 = 26.46 + 13.23\\T_{1} = 14.36 N

7 0
3 years ago
Other questions:
  • How is the thermal energy from the air surrounding the radiator transferred to the air in the rest of the room?
    7·1 answer
  • One deterrent to burglary is to leave your front porch light on all the time. If your local power utility sells energy at 17¢ pe
    13·1 answer
  • HELP, what are 2 chemical properties of Tungsten.
    15·2 answers
  • The built-up beam is formed by welding together the thin plates of thickness 5 mm. determine the location of the shear center o.
    15·1 answer
  • Accelerated motion is represented by a _____ line on a nonlinear distance-time graph.
    15·2 answers
  • If a 5000-kg is moving at a speed of 43 m/s, what is its momentum?
    8·1 answer
  • What happened to the combined energy of the two sleds when they collided?
    7·1 answer
  • A 150 kg bike takes a roundabout with a radius of 53.0 m. The roundabout it’s only ¾ of a circle. the time taken was 0.35 minute
    14·1 answer
  • A 600kg lifts starts from rest. It moves upward for 3.00 s with a constant acceleration until it reaches its final speed of 1.55
    15·1 answer
  • Electrical force is much weaker than the force of gravity true or false. ​
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!