Home
Class 12
PHYSICS
An elevator has full load capacity 800 k...

An elevator has full load capacity 800 kg. Frictional force on the elevator is 4000 N. If elevator is going down with constant speed 2.0 m/s, then the power applied by electric motor at full load is lose to : (1 HP = 746 W, g = 10 `m//s^2`)

A

`-10.72 HP`

B

`-32.17 HP`

C

`+10.72 HP`

D

`+ 32.17 HP`

Text Solution

Verified by Experts

The correct Answer is:
A
`P = vecF.vecv = F v cos 180^@`
`= -Fv`
`= -(8000 - 4000) xx 2`
`= - 8000 W`
on `P = -(8000)/(746) HP`.
`= -10.72 HP`.
Promotional Banner

Similar Questions

Explore conceptually related problems

A 60 HP electric motor lifts an elevator having a maximum total load capacity of 2000 kg. if the frictional force on the elevator is 4000 N, the speed of the elevator at full load is close to : ( 1 HP = 746 W, g = 10 ms ^( - 2 ) )

A 120 HP electric motor lifts an elevator having a maximum total load capacity of 3000 kg. If the frictional force on the elevator is 6000N, the speed of the elevator at full load is close to : (1 HP = 746 W, g = 10 ms^(-2) ).

A man of mass 50 kg is standing in an elevator. If elevator is moving up with an acceleration (g)/(3) then work done by normal reaction of elevator floor on man when elevator moves by a distance 12 m is (g=10 m//s^(2)) :-

A block of mass 2 kg rests on the floor of an elevator , which is moving down with an acceleration 'g' , then the apparent weight of the block is [ take g = 10 m//s^(2) ]

An elevator weighing 500 kg is to be lifted up at a constant velociyt of 0.20 m/s. What would be the minimum horsepower of the motor to be used?

Suppose the ceiling in the previous problem is that the elevator which is going up with an acceleration of 2.0 m/s^2 . Find the elongations.

A lorry of mass 2000 kg is traveling up a hill of certain height at a constant speed of 10 m/s. The frictional resistance is 200 N, then the power expended by the coolie is : (g=10 m//s^(2))

An elevator and its load weigh a total of 800kg Find the tension T in the supporting cable when the elevator originally moving downwards at 20m//s is brought to rest with constant retardation in a distnce of 50m .

An elevator and its load weigh a total of 1600 kg. Find the tension T in the supporting cable when the elevator, originally moving downward at 20 m/s is brought to rest with constant acceleration in a distance of 50 m.