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
Varvara68 [4.7K]
2 years ago
10

A sled of mass 50 kg is pulled along a snow-covered, flat ground. The static friction coefficient is 0.3 and the kinetic frictio

n coefficient is 0.1.
Draw a FBD of all the forces acting on the sled.
What is the weight of the sled?
What force is needed to start the sled moving?
What force is needed to keep the sled moving at a constant velocity?
Physics
1 answer:
Diano4ka-milaya [45]2 years ago
8 0

Answer:

a) We kindly invite you to see below the Free Body Diagram of the forces acting on the sled.

b) The weight of the sled is 490.35 newtons.

c) A force of 147.105 newtons is needed to start the sled moving.

d) A force of 49.035 newtons is needed to keep the sled moving at a constant velocity.

Explanation:

a) We kindly invite you to see below the Free Body Diagram of the forces acting on the sled. All forces are listed:

F - External force exerted on the sled, measured in newtons.

f - Friction force, measured in newtons.

N - Normal force from the ground on the mass, measured in newtons.

W - Weight, measured in newtons.

b) The weight of the sled is determined by the following formula:

W = m\cdot g (1)

Where:

m - Mass, measured in kilograms.

g - Gravitational acceleration, measured in meters per square second.

If we know that m = 50\,kg and g = 9.807\,\frac{m}{s^{2}}, the weight of the sled is:

W = (50\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)

W = 490.35\,N

The weight of the sled is 490.35 newtons.

c) The minimum force needed to start the sled moving on the horizontal ground is:

F_{min,s} = \mu_{s}\cdot W (2)

Where:

\mu_{s} - Static coefficient of friction, dimensionless.

W - Weight of the sled, measured in newtons.

If we know that \mu_{s} = 0.3 and W = 490.35\,N, then the force needed to start the sled moving is:

F_{min,s} = 0.3\cdot (490.35\,N)

F_{min,s} = 147.105\,N

A force of 147.105 newtons is needed to start the sled moving.

d) The minimum force needed to keep the sled moving at constant velocity is:

F_{min,k} = \mu_{k}\cdot W (3)

Where \mu_{k} is the kinetic coefficient of friction, dimensionless.

If we know that \mu_{k} = 0.1 and W = 490.35\,N, then the force needed to keep the sled moving at a constant velocity is:

F_{min,k} = 0.1\cdot (490.35\,N)

F_{min,k} = 49.035\,N

A force of 49.035 newtons is needed to keep the sled moving at a constant velocity.

You might be interested in
I need help!!!! I don’t understand physical science at all.
allochka39001 [22]
B is the correct answer
3 0
2 years ago
Students measured the mass of 25.0 mL of water and found it be 25.4 g. The accepted mass is 25.0 g. What is the percent error of
Andre45 [30]
Well first of all, I think the students may have been correct. 
If they didn't use distilled water, and if it wasn't exactly at 
standard temperature, then the mass of  25.0 mL  could
very well be  25.4 grams.  We don't know that there was
any 'error' in their measurement at all.
But the question says there was, so we'll do the math:

The 'error' was  (25.4 - 25.0) = +0.4 gram

As a fraction of the 'real' value, the error was

                            +0.4 / 25.0  =  +0.016 .

To change a decimal to a percent, move the
decimal point two places that way  ===> .

                           + 0.016  =  +1.6 % .

     
Their measurement was 1.6% too high.

Let's not call it an 'error'.  Let's just call it a 'discrepancy'
between the measured value and the 'accepted' value.  OK ?
4 0
3 years ago
Read 2 more answers
Compare the energy consumption of two commonly used items in the household. Calculate the energy used by a 1.40 kW toaster oven,
andrew-mc [135]

Energy = (power) x (time)

-- <u>For the toaster:</u>

Power = 1.4 kW  =  1,400 watts

Time = 5.4 minutes = 324 seconds

Energy = (1,400 W) x (324 s)  =  453,600 Joules

-- <u>For the CFL bulb:</u>

Power = 11 watts

Time = 10.5 hours = 37,800 seconds

Energy = (11 W) x (37,800 s)  =  415,800 Joules

-- The toaster uses energy at 127 times the rate of the CFL bulb.

-- The CFL bulb uses energy at 0.0079 times the rate of the toaster.

-- The toaster is used for 0.0086 times as long as the CFL bulb.

-- The CFL bulb is used for 116.7 times as long as the toaster.    

-- The toaster uses 9.1% more energy than the CFL bulb.

-- The CFL bulb uses 8.3% less energy than the toaster.  

7 0
3 years ago
If the current through a 20-Ω resistor is 8.0 A , how much energy is dissipated by the resistor in 1.0 h ? Express your answer w
marshall27 [118]

Answer:

P(3600)=593.247W

Explanation:

First, let's find the voltage through the resistor using ohm's law:

V=IR=20*8=160V

AC power as function of time can be calculated as:

P(t)= V*I*cos(\phi)-V*I*cos(2 \omega t-\phi)  (1)

Where:

\phi=Phase\hspace{3}angle\\\omega= Angular\hspace{3}frequency

Because of the problem doesn't give us additional information, let's assume:

\phi=0\\\omega=2 \pi f=2*\pi *(60)=120\pi

Evaluating the equation (1) in t=3600 (Because 1h equal to 3600s):

P(3600)=160*8*cos(0)-160*8*cos(2*120\pi*3600-0)\\P(3600)=1280-1280*cos(2714336.053)\\P(3600)=1280-1280*0.5365255751\\P(3600)=1280-686.7527361=593.2472639\approx=593.247W

5 0
3 years ago
According to the pressure-flow hypothesis, which of the following statements is not true?
adelina 88 [10]
"The movement of water into a nutrient-rich region of the phloem decreases the pressure in that region" is the statement that is not true according <span>to the pressure-flow hypothesis. The correct option among all the options that are given in the question is the fourth option or the last option. I hope it helps you.</span>
7 0
3 years ago
Read 2 more answers
Other questions:
  • People have proposed driving motors with the earth's magnetic field. This is possible in principle, but the small field means th
    15·1 answer
  • At the instant the traffic light turns green, an automobile that has been waiting at an intersection starts ahead with a constan
    10·1 answer
  • One end of a uniform well-lagged metal bar of length 0.80 m and cross-sectional area of
    11·1 answer
  • what is the answer to the question "Two boys of equal mass go up to the first floor of a building. Boy A takes the stairs, boy B
    10·1 answer
  • Using the graph below: What was the instantaneous velocity at t = 12 seconds? What was the distance and displacement of this obj
    14·1 answer
  • organisims that have a physical trait that makes it easier for them o access food supply are unlikely to pass on that trait to t
    14·1 answer
  • Pure rain, egg yolks, battery acid, and milk are all examples of acids.<br> True or false?
    6·1 answer
  • A person uses their hand to lift a 0.05-kg guniea pig from the ground at a constand speed.What is the force applied by the perso
    9·1 answer
  • A vehicle has an initial velocity of 30 meters per second. 30 seconds later, it is traveling at a velocity of 60 meters per seco
    15·1 answer
  • Need Help Please and Thank You). Question 1: Explain how longitudinal waves and transverse waves are similar to each other and d
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!