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
Likurg_2 [28]
2 years ago
12

An Olympic skier moving at 20.0 m/s down a 30.0o slope encounters a region of wet snow, of

Physics
1 answer:
Sonja [21]2 years ago
8 0

Answer:

Option B

Explanation:

Forces acting on the skier-

F1 =  -mg sin(30) down the slope  

F2 = -mg cos(30)

F3 = friction force  = 0.74 mg cos(30)  

Net force, down the slope  

=  -mg sin(30)+ 0.74 mg cos(30)\\= mg(.74 cos(30)-sin(30))\\= 0.14mg\\= 1.38m

Acceleration = F/m= 1.38 m/s2  

Acceleration remains constant, initial speed is 20 m/s

Speed at time t is 1.38t- 20 m/s

Distance down the slope at time t is 0.69t^2- 20t

When the skier stops, her speed is 0. Thus,  

, 1.38t- 20= 0\\t= 20/1.38\\= 14.5 seconds

Distance travelled in 14.5 seconds =  (0.69)(14.52- 20(14.5)= -145 m(negative because it is down the slope).

Option B is correct

You might be interested in
A cardboard box sits on top of a concrete sidewalk where the coefficient of friction between the surfaces is 0.4. The mass of th
Sloan [31]

Answer:

Fg = 98.1 [N]; N = 98.1 [N]; Ff = 39.24 [N]; a = 2.076[m/^2]

Explanation:

To solve this problem, we must make a free body diagram and interpret each of the forces acting on the box. In the attached diagram we can find the free body diagram.

The gravitational force is equal to:

Fg = (10 * 9.81) = 98.1 [N]

Now by summing forces on the Y axis equal to zero, we can find the normal force exerted by the surface.

N - Fg = 0

N = Fg

N = 98.1 [N]

The friction force is defined as the product of normal force by the coefficient of friction.

Ff = N * μ

Ff = 98.1 * 0.4

Ff = 39.24 [N]

By the sum forces on the x-axis equal to the product of mass by acceleration (newton's second law), we can find the value of acceleration.

60 - Ff = m * a

60 - 39.24 = 10 * a

a = 2.076[m/^2]

6 0
3 years ago
Train cars are coupled together by being bumped into one another. Suppose two loaded cars are moving toward one another, the fir
tia_tia [17]

Answer:

7560 Joules

Explanation:

m_1 = Mass of first car = 1.5\times 10^5\ kg

m_2 = Mass of second car = 2\times 10^5\ kg

u_1 = Initial Velocity of first car = 0.3 m/s

u_2 = Initial Velocity of second car = -0.12 m/s

v = Velocity of combined mass

As linear momentum of the system is conserved

m_1u_1 + m_2u_2 =(m_1 + m_2)v\\\Rightarrow v=\frac{m_1u_1 + m_2u_2}{m_1 + m_2}\\\Rightarrow v=\frac{1.5\times 10^5\times 0.3 + 2\times 10^5\times -0.12}{1.5\times 10^5 + 2\times 10^5}\\\Rightarrow v=0.06\ m/s

Energy lost is

\Delta E=\Delta E_i-\Delta E_f\\\Rightarrow \Delta=\frac{1}{2}(m_1u_1^2 + m_2u_2^2-(m_1+m_2)v^2)\\\Rightarrow \Delta=\frac{1}{2}(1.5\times 10^5\times 0.3^2 + 2\times 10^5\times (-0.12)^2-(1.5\times 10^5 + 2\times 10^5)\times 0.06^2)\\\Rightarrow \Delta=7560\ J

The Energy lost in the collision is 7560 Joules

7 0
3 years ago
You have a sealed glass jar full of air. If you put it in the freezer, what happens to the gas pressure in the jar?
xz_007 [3.2K]
The pressure inside decreases
8 0
3 years ago
what is the answer to what does a 150 kg roller coaster traveling at 10m/s has how much kinetic energy
Svetllana [295]
The answer to the question is 15 kinetic energy
5 0
3 years ago
Which of the following has the greatest amount of kinetic energy a)slice of pizza b)a person at the top of the stairs c)wind d)a
Talja [164]

Answer:

c)wind

Explanation:

Wind from the given choices will have the greatest amount of kinetic energy.

Kinetic energy is the energy due to motion of a body. It is different from the energy at rest in a body.

  • Wind is air in motion.
  • Wind energy is a form of kinetic energy in motion.

A book on a table, a slice of pizza and a person at the top of the stairs are all at rest and will possess potential energy.

7 0
3 years ago
Other questions:
  • A spring stores 10. joules of elastic potential
    11·2 answers
  • The voltage of electricity traveling away from a power plant is very high. How high may it be? Why is the voltage so high?
    10·1 answer
  • There are 92 naturally occurring elements. How does this relate to the number of compounds?
    12·1 answer
  • What happens to the total mass of a substance undergoing a physical change?
    7·1 answer
  • What would the velocity of a wave traveling in a medium change?
    8·1 answer
  • Vector A has a magnitude of 6.0 m and points 30° north of east. Vector B has a magnitude of 4.0 m and points 30° west of south.
    13·1 answer
  • A 26-cm-long wire with a linear density of 20 g/m passes across the open end of an 86-cm-long open-closed tube of air. If the wi
    9·1 answer
  • What is the difference between mass density and weight density?
    6·1 answer
  • You walk to the corner store at 2 m/s for a total time of 76 seconds. What is the distance to the store?
    5·2 answers
  • A TMS (transcranial magnetic stimulation) device creates very rapidly changing magnetic fields. The field near a typical pulsed-
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!