22 Answered Questions for the topic Power


A rectangular room of length 6 metres has six 18 W LED lights.

What is the maximum width of the room if the lamp power density requirement of 5W/m^2 (5 Watts per metre squared) is to be met?


How high can a hike climb with the energy from a candy bar?

A candy bar label says it has 240 Calories (240,000 calories). Typical efficiency of energy conversion for a human is 25%. If a 68kg person were to use the energy in the candy bar to climb a... more


A projectile of mass 5.0 kg is shot

A projectile of mass 5.0 kg is shot horizontally with an initial speed of 17 m/s from a height of 25.0 m above a flat desert surface. For the instant before the projectile hits the surface,... more


Work, power and energy

Heights:Point A=65m, Point B=52 m, Point C=25mThe total mass of the roller coaster is 650 kg. a) If it takes a force of 2760 N [parallel to the track] to pull the roller coaster up to point A, and... more


How to simplify exponent fractions

32×42÷63=3×3×4×4/6×6×6 How do you simplify this, and what is the rule of it? (As a fraction, not a decimal) The part underlined is a fraction.


Finding the speed of an object

A certain horse can maintain 1.0 hp of output for 2.4 hours with an efficiency of 72%. The horse is pulling a 220 kg object along a horizontal ground. The coefficient of kinetic friction between... more


Physics Power and Work

A 49kg bicycle rider delivers an average of 0.28 hp. The mass of the bicycle is 2.1kg and the hill she is climbing is 245m tall. How much time will this take?
Power Physics Work


Machine Efficiency

A force of 455 N is exerted in pulling 15 m of rope using a pulley system to lift a 935 N object 5 m. What is the efficiency of the system?   ...What is the difference between Work in and Work... more
Power Exponents


Evaluating as single power

a) x4 ÷ x7 b) (1/2)-8 (1/2)6 c) 3-2x 36     _____        33  


Work energy Power doubt

An object of mass m, initially at rest under the action of a constant force F attains a velocity v in time t. Then the average power is supplied to mass is ?
Power Circuits


time elapsed in an LR circuit

An LR circuit having time constant of 50 ms is connected with an ideal battery of emf E . prove that the time elapsed before the power dissipated in heat reaches half its maximum value is 61ms
Power Work Energy


What is the change in gravitational potential energy, in Joules?

A 20.0 kg box slides up a 12.0 m long incline at an angle of 30.0 degrees with the horizontal. A force of 150 N is applied to the box to pull it up the incline. The applied force makes an angle of... more


Physics Problems (2) : Work & Power

How much power is expended to raise a 300 kg roller coaster car to the top of a 35 m hill in 10 seconds? How much potential energy does the roller coaster car have at the top of the... more


Physics Problems (2) : Work & Power

How much potential energy does 8 million kg of water have as it drops 50 m over Niagara Falls? If a 8 million kg of water flows over Niagara Falls each second, calculate the power available at... more


Physics Problems (2) : Work & Power

A weightlifter lifts a 50 kg barbell 2.5 meters into the air. How much work does she do on a barbell? How much potential energy does the barbell have at the top? If she lifts the barbell in 2... more
Power Physics


Physics Term: Power

Define power and explain thoroughly how it applies to a rollercoaster using physics terms.


what is the meaning of inclination 1 in 20

A bus of mass 6 metric tons is pulled at a speed o 18KMPH  on a smooth incline of inclination 1 in 20.power of the engine is.  


Car have mass m,its engine delivers power P.what's the minimum time in which car can be accelerated from rest to speed v

A car of mass m has an engine which can deliver power P.The minimum time in which car can be accelerated from rest to a speed v is(a) (mv^2)/2P(b) Pmv^2(c) 2Pmv^2(d) (mv^2)P/2
Power Work Energy


Find mechanical power?

The blades of a wind mill sweep out a circle of area A.If wind flows with velocity v perpendicular to blades of wind mill and its density is D,then the mechanical power received by wind mill is (a)... more
Power Work Energy


Find Power ?

A pump is used to pump a liquid of density D continuously through a pipe of cross section area A.If liquid is flowing with speed v,then power of pump is(a) (DAv^2)/3(b) (DAv^2)/2(c) 2DAv^2(d)... more
Power Expressions


(cw)^h = Complete this expression

  (cw)^h =         Complete this expression

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