Question

An elevator has a mass of 2,000 kg and is carrying a load of passengers with...

An elevator has a mass of 2,000 kg and is carrying a load of passengers with a combined mass of 250 kg. A constant friction force of 3,000 N retards the motion of the elevator. recall; P = dW/dt

a) How much power must the motor provide to lift the car at a constant speed of 4 m/s?

b) How much power is required to provide the elevator car with 9.8 m/s^2 of acceleration at 1 m/s vs 4 m/s?

Homework Answers

Answer #1

here,

mass of elevator , m1 = 2000 kg

mass of passengers ,m2 = 250 kg

friction force , ff = 3000 N

a)

the net force required for constant speed , F = (m1 + m2) * g + ff

F = ( 2000 + 250) * 9.81 + 3000 N

F = 2.51 * 10^4 N

the power required , P = F * v

P = 1 * 10^5 W

b)

accelration , a = 9.8 m/s^2

the net force required , F = (m1 + m2) * g + ff + (m1 + m2) * a

F = ( 2000 + 250) * (9.81 + 9.81 ) + 3000 N

F = 47145 N

for v1 = 1 m/s

the power required , P1 = F * v1

P1 = 4.71 * 10^4 W

for v2 = 4 m/s

the power required , P2 = F * v2

P2 = 1.88 * 10^5 W

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
An elevator car has a mass of 1600 kg and is carrying passengers having a combined...
An elevator car has a mass of 1600 kg and is carrying passengers having a combined mass of 300 kg. A constant friction force of 4000 N retards its motion. How much power must a motor deliver to lift the elevator car and its passengers at a constant speed of 3.00 m/s _____. a. 4.39e4 W b. 6.79 e4 W c. 5.02e4 W d. 2.62e4 W
An elevator car has a mass of 1500 kg carry 3 passengers with a total mass...
An elevator car has a mass of 1500 kg carry 3 passengers with a total mass of 330 kg. The lift operates with a constant frictional force of 2 700 N working against the motion of the elevator. How much power must the motor deliver to the elevator cart to keep it moving at a constant speed of 2.4 ms-1 ? How much power would need to be supplied by the motor if it was 70% efficient?
An elevator car including the passengers has a mass of 1100 kg and travels downwards at...
An elevator car including the passengers has a mass of 1100 kg and travels downwards at constant speed of 4.000 m/s for 32.00 m. The force of friction averaging 80.00 N acts on the elevator. The work done by the force of gravity; the work done by the force of friction; and the work done by the cable supporting the elevator during the 32.00 m excursion were (in that order, in kJ): Answer: 345.0; -2.560; -342.4
An elevator filled with passengers has a mass of 1583 kg. (a) The elevator accelerates upward...
An elevator filled with passengers has a mass of 1583 kg. (a) The elevator accelerates upward from rest at a rate of 1.20 m/s2 for 2.00 s. Calculate the tension in the cable (in N) supporting the elevator. (b)The elevator continues upward at constant velocity for 9.22 s. What is the tension in the cable (in N) during this time? (c)The elevator decelerates at a rate of 0.600 m/s2 for 4.00 s. What is the tension in the cable (in...
(13%) Problem 8:   An elevator motor lifts a 2300-kg load a height of 38 m in...
(13%) Problem 8:   An elevator motor lifts a 2300-kg load a height of 38 m in 13.5 s. Part (a) Find the useful power output of the elevator motor, if it also increases the speed from rest to 3.9 m/s. Assume that the total mass of the counterbalanced system is 10,000 kg — so that only 2300 kg is raised in height, but the full 10,000 kg is accelerated. Part (b) How much does it cost, in dollars per hour,...
(a) Find the useful power output of an elevator motor that lifts a 2400-kg load a...
(a) Find the useful power output of an elevator motor that lifts a 2400-kg load a height of 35.0 m in 12.0 s, if it also increases the speed from rest to 4.0 m/s. Note that the total mass of the counterbalanced system is 10000 kg—so that only 2400 kg is raised in height, but the full 10000 kg is accelerated. (b)What does it cost, if electricity is $0.09 per kW ⋅ h ? Thank you
A loaded ore car has a mass of 950 kg and rolls on rails with negligible...
A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 28.5° above the horizontal. The car accelerates uniformly to a speed of 2.05 m/s in 12.5 s and then continues at constant speed. (a) What power must the winch motor provide when the car is moving at constant speed? kW...
A(n) 603 kg elevator starts from rest. It moves upward for 3.88 s with a constant...
A(n) 603 kg elevator starts from rest. It moves upward for 3.88 s with a constant acceleration until it reaches its cruising speed of 1.78 m/s. The acceleration of gravity is 9.8 m/s 2 . Find the average power delivered by the elevator motor during this period. Answer in units of kW.
An express lift (elevator) takes a 70 kg passenger from street level to the top of...
An express lift (elevator) takes a 70 kg passenger from street level to the top of a 400 m skyscraper in 4 minutes. The mass of the elevator itself is 500 kg a. How much gravitational potential energy does the passenger gain on the way up? b. At what rate (energy per second) is the passenger gaining potential energy? c. At what rate is the lift plus the passenger gaining potential energy? d. What power is the lift plus the...
One elevator arrangement includes the passenger car, a counterweight, and two large pulleys, as shown in...
One elevator arrangement includes the passenger car, a counterweight, and two large pulleys, as shown in (Figure 1). Each pulley has a radius of 1.3 m and a moment of inertia of 370 kg?m2. The top pulley is driven by a motor. The elevator car plus passengers has a mass of 3200 kg, and the counterweight has a mass of 2600 kg. Part A If the motor is to accelerate the elevator car upward at 1.5 m/s2, how much torque...