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
sertanlavr [38]
3 years ago
7

A brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800.0 N on him. Th

e mass of the losing player plus equipment is 90.0 kg, and he is accelerating backward at 1.20 m/s².
(a) What is the force of friction between the losing player's feet and the grass?
(b) What force does the winning player exert on the ground to move forward if his mass plus equipment is 110.0 kg?
Physics
1 answer:
ipn [44]3 years ago
7 0

Answer:

a) F_{fric} = 692 N

b) F_{applied} = 932 N

Explanation:

a)

According to newton's second law of motion, acceleration of an object is directly proportional to the net force acting on it. When there is no net force force acting on the body, there is no acceleration. A force is a push or a pull, and the net force ΣF is the total force, or sum of the forces exerted on an object  in all directions.

F_{net}  ∝ a

F_{net} =  ma

F_{applied} - F_{fric} = ma

Given data:

F_{applied} = 800 N

Mass = m = 90 kg

acceleration = a = 1.2 m/s²

F_{fric} = ?

800 - F_{fric} = (90)(1.2)

F_{fric} = 692 N

b)

According to newton's second law of motion,

F_{net}  ∝ a

F_{net} =  ma

F_{applied} - F_{fric} = ma

Given data:

If we assume the same friction and acceleration between player's feet and ground as calculated in part a

F_{fric} = 692 N

acceleration = a = 1.2 m/s²

We take the equal mass to the total mass of both the players because when the winning player push losing player backward, he exert force on the ground not only due to his mass but also due to the mass of losing player.

Mass = M = m₁ + m₂ = 110 kg + 90 kg

= 200 kg

F_{applied} = ?

F_{applied} - 692 N = (200)(1.2)

F_{applied} = 692 + 240

F_{applied} = 932 N

You might be interested in
The actual mechanical advantage of any machine is its__________divided by its________________
zaharov [31]

Answer: Load divided by it effort

Explanation:

Mechanical advantage of any machine is its load divided by its effort

4 0
3 years ago
a 2 meters tall person is located 5 meters from a camera lens (camera lens are convex lenses). the lens has a focal length of 35
ki77a [65]
Sorry that you got your answer late but the answer is 0.035m
3 0
3 years ago
Tim and Rick both can run at speed Vr and walk at speed Vw, with Vr > Vw.
miss Akunina [59]

Answer:

Δt =  \frac{2D}{Vw+Vr} - \frac{D}{2Vr} - \frac{D}{2Vw}

Explanation:

Hi there!

Using the equation of speed for the whole trip, we can obtain the time each one needed to cover the distance D.

The speed (v) is calculated by dividing the traveled distance (d) over the time needed to cover that distance (t):

v = d/t

Rick traveled half of the distance at Vr and the other half at Vw. Then, when v = Vr, the distance traveled was D/2 and the time is unknown, Δt1:

Vr = D/ (2 · Δt1)

For the other half of the trip the expression of velocity will be:

Vw = D/(2 · Δt2)

The total time traveled is the sum of both Δt:

Δt(total) = Δt1 + Δt2

Then, solving the first equation for Δt1:

Vr = D/ (2 · Δt1)

Δt1 = D/(2 · Vr)

In the same way for the second equation:

Δt2 = D/(2 · Vw)

Δt + Δt2 = D/(2 · Vr) + D/(2 · Vw)

Δt(total) = D/2 · (1/Vr + 1/Vw)

The time needed by Rick to complete the trip was:

Δt(total) = D/2 · (1/Vr + 1/Vw)

Now let´s calculate the time it took Tim to do the trip:

Tim walks half of the time, then his speed could be expressed as follows:

Vw = 2d1/Δt  Where d1 is the traveled distance.

Solving for d1:

Vw · Δt/2 = d1

He then ran half of the time:

Vr = 2d2/Δt

Solving for d2:

Vr · Δt/2 = d2

Since d1 + d2 = D, then:

Vw · Δt/2 +  Vr · Δt/2 = D

Solving for Δt:

Δt (Vw/2 + Vr/2) = D

Δt = D / (Vw/2 + Vr/2)

Δt = D/ ((Vw + Vr)/2)

Δt = 2D / (Vw + Vr)

The time needed by Tim to complete the trip was:

Δt = 2D / (Vw + Vr)

Let´s find the diference between the time done by Tim and the one done by Rick:

Δt(tim) - Δt(rick)

2D / (Vw + Vr) - (D/2 · (1/Vr + 1/Vw))

\frac{2D}{Vw+Vr} - \frac{D}{2Vr} - \frac{D}{2Vw} = Δt

Let´s check the result. If Vr = Vw:

Δt = 2D/2Vr - D/2Vr - D/2Vr

Δt = D/Vr - D/Vr = 0

This makes sense because if both move with the same velocity all the time both will do the trip in the same time.

8 0
3 years ago
What is the value of the composite constant (Gme,/r2e) to be multiplied by the mass of the object mo, in equation below:
Sedbober [7]

To solve this problem we will apply the definitions given in Newtonian theory about the Force of gravity, and the Force caused by weight. Both will be defined below, and in equal equilibrium condition to clear the variable concerning acceleration due to gravity. Finally, with the values provided in the statement, it will be replaced.

The equation for the gravitational force between the Earth and the object on the surface of the Earth is

F_g = \frac{Gm_em_o}{r^2_e}

Where,

G = Universal gravitational constant

m_e = Mass of Earth

r_e= Distance between object and center of earth

m_o= Mass of Object

The equation for the gravitational pulling force on the object due to gravitational acceleration is

F_g = m_o g

Equation the two expression we have

m_o g = \frac{Gm_em_o}{r_e^2}

g = \frac{Gm_e}{r_e^2}

This the acceleration due to gravity which is composite constant.

Replacing with our values we have then

g = \frac{(6.67*10^{-11}N\cdot m^2/kg^2)(5.98*10^{24}kg)}{6378km(\frac{10^3m}{1km})^2}

g = 9.8m/s^2

The value of composite constant is 9.8m/s^2. Here, the composite constant is nothing but the acceleration due to gravity which is constant always.

8 0
3 years ago
The brakes of a lorry are in a poor condition
Vlada [557]

Answer:

friction

Explanation:

Her brakes will squeak and possibly slide or skid on concrete due to her brakes.

BUT it really depends on the condition of the wheels. Now it matters on the surface as well. Has the road been eroded? what has happened with her brakes? and what texture are the wheels? can seismic waves travel through them?

5 0
3 years ago
Other questions:
  • What is the main optical element of a refracting telescope?
    9·1 answer
  • A golfer hits a golf ball with a velocity of 36.0 meters/second at an angle of 28.0°. If the hang time of the golf ball is 3.44
    14·1 answer
  • A sled of mass 10 kg slides along the ice. it has an initial speed of 2 m/s but stops because of friction. How much work is done
    6·2 answers
  • Layers of Earth's Atmosphere
    10·1 answer
  • Sam is observing the velocity of a car at different times. After two hours, the velocity of the car is 54 km/h. After four hours
    5·1 answer
  • A thin, flat washer is a disk with an outer diameter of 14 cm and a hole in the center with a diameter of 7 cm. The washer has a
    9·1 answer
  • A woman lifts a barbell 2.0 m in 5.0 s. If she lifts it the same distance in 10 s, the work done by her is:______
    6·1 answer
  • The total length of the cord is L = 7.00 m, the mass of the cord is m = 7.00 g, the mass of the hanging object is M = 2.50 kg, a
    6·1 answer
  • a 5.0 kg ball is dropped from a 2.5 m high window. what is the velocity of the ball just before it hits the ground?
    13·1 answer
  • A cyclist turns a corner with a radius of 50m at a speed of 10m/s. What is the cyclist's acceleration?
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!