Physics, 22.11.2019 00:31 mandyO1

Acart loaded with bricks has a total mass of 17 kg and is pulled at constant speed by a rope. the rope is inclined at 25 degrees above the horizontal and the cart moves 22.8 m on a horizontal floor. the coefficient of kinetic friction between ground and cart is 0.6. the acceleration of gravity is 9.8 m/s^2.a. what is the normal force exerted on the cart by the floor? answer in units of n. b. how much work is done on the cart by the rope? answer in kjc. note: the energy change due to friction is a loss of energy. what is the energy change wf due to friction ? answer in kj.

Answers: 1

Show answers

Answers

Answer from: durham953

a) N = 382.9 N

b) W = 5.237 kJ

c) ΔE = Wf =- 5.237 kJ

Explanation:

Newton's second law :

∑F = m*a Formula (1)

∑F : algebraic sum of the forces in Newton (N)

m : mass in kilograms (kg)

a : acceleration in meters over second square (m/s²)

Known data

m=17 kg : mass of the cart

θ = 25°: angle of the Tension force above the horizontal

μk= 0.60: coefficient of kinetic friction between the cart and the ground

g = 9.8 m/s²: acceleration due to gravity

Forces acting on the cart

We define the x-axis in the direction parallel to the movement of the cart on the floor and the y-axis in the direction perpendicular to it.

W: Weight of the cart : In vertical direction downaward

N : Normal force : In vertical direction the upaward

T : Force applied to the cart

f : Friction force: In horizontal direction

Calculated of the weight of the cart

W= m*g = (17 kg)*(9.8 m/s²)= 166.6 N

x-y components T

Tx = Tcosθ = T*cos(25)°

Ty = Tsinθ = T*sin(25)°

Calculated of the Normal force

∑Fy = m*ay ay = 0

N-W+Ty= 0

N-W+T*sin(25)= 0

N = 490 -T*sin(25)° Equation (1)

Calculated of the kinetic friction force (fk):

fk=μk*N= 0.6*( 490 -T*sin(25)°

fk = 0.6*490 -0.6T*sin(25)°

fk = 294 -0.6¨*sin(25)° T Equation (2)

Newton's second law to the cart

∑F = m*a

a =0 because the cart moves at constant speed

∑F = 0

Tx-fk=0

T*cos(25)°= fk Equation (3)

a) Calculated of the Normal force

Equation (2) = Equation (3) = fk

294 -0.6¨*sin(25)° T=T*cos(25)°

294 =T(0.6¨*sin(25)°)+ T(cos(25)°)

294 =T(0.6¨*sin(25)° + cos(25)°)

294 =T(0.6¨*sin(25)°+(cos(25)°)

294 = T(1.16)

T = (294) /(1.16)

T = 253.45 N

We replace T = 253.45 N in the equation (1)

N = 490 -T*sin(25)°

N = 490 - ( 253.45)*sin(25)°

N = 382.9 N

b) Work done by the rope on the cart

W = (Tx) *d

W = (T*cos(25)°)*(22.8)

W = (253.45*cos(25)°)(22.8) (N*m)

W = 5237.24 (N*m)

W = 5237.24 J = 5.237 kJ

What is the energy change Wf due to friction ?

ΔE= Wfk

ΔE : Energy change

Wfk : Work done by fk

in the Equation (3) :

T*cos(25)°= fk = ( 253.45) N*cos(25)° = 229.7 N

ΔE= - fk*d

ΔE= - (229.7 N)*(22.8 )m

ΔE= - 5.237 kJ =Wfk

Answer from: Quest

Amethod of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

Answer from: Quest

True aroms consist made of nuclesus that surrousded by 0n protons neurologist me asap what or else and

Another question on Physics

Physics, 21.06.2019 17:20

American eels (anguilla rostrata) are freshwater fish with long, slender bodies that we can treat as uniform cylinders 1.0 m long and 10 cm in diameter. an eel compensates for its small jaw and teeth by holding onto prey with its mouth and then rapidly spinning its body around its long axis to tear off a piece of flesh. eels have been recorded to spin at up to 14 revolutions per second when feeding in this way. although this feeding method is costly in terms of energy, it allows the eel to feed on larger prey than it otherwise could. 1.a field researcher uses the slow-motion feature on her phones camera to shoot a video of an eel spinning at its maximum rate. the camera records at 120 frames per second. through what angle does the eel rotate from one frame to the next? 2. the eel is observed to spin at 14 spins per second clockwise, and 10 seconds later it is observed to spin at 8 spins per second counterclockwise. what is the magnitude of the eels average angular acceleration during this time? 3. the eel has a certain amount of rotational kinetic energy when spinning at 14 spins per second. if it swam in a straight line instead, about how fast would the eel have to swim to have the same amount of kinetic energy as when it is spinning? 4.a new species of eel is found to have the same mass but one-quarter the length and twice the diameter of the american eel. how does its moment of inertia for spinning around its long axis compare to that of the american eel?

Answers: 1

Answer

Physics, 21.06.2019 23:30

The velocity of car is 80.0 miles per hour. what is the velocity of car in meters per second? (1 km -0.621 miles) m/s

Answers: 2

Answer

Physics, 22.06.2019 03:30

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

Answers: 3

Answer

Physics, 22.06.2019 04:00

The long handle on a rake is a(n) a. lever b. screw c. wedge d. inclined plane

Answers: 2

Answer

You know the right answer?

Acart loaded with bricks has a total mass of 17 kg and is pulled at constant speed by a rope. the ro...

Questions