Work, power & energy Questions and Answers

If your home heating system brings air with a temperature of 5 C and specific humidity of 1 3 g kg inside and heats it to 21 C what is the relative humidity of that air What is the specific humidity of air at 21 C with 50 relative humidity What is the difference in SH between air at 1 3g kg and air at 21 C with 50 relative humidity Given an air parcel with a temperature of 33 C and relative humidity of 95 what is the specific humidity of the parcel Flag question Question 12 Question 121 pts What is the Tdp of an air parcel with a temperature of 33 C and relative humidity of 95 What is the difference in SH between an air parcel at 33 C and 95 relative humidity and an air parcel at 21 C with 50 relative humidity Given an air parcel with a temperature of 16 C and a Tdp of 13 C what is the specific humidity of the atmosphere Given an air parcel with a temperature of 16 C and a Tdp of 13 C what is the relative humidity of the atmosphere Given an air parcel with a temperature of 34 C and a Tdp of 13 C what is the relative humidity of the atmosphere

Anonymous Quiz 26 a The kinetic energy of a system cannot be changed without changing the momentum 43 b The kinetic energy of a system can be changed without changing the momentum 21 c The momentum of a system cannot be changed without changing its kinetic energy X 10 d A system cannot have energy without having momentum

Q6 Which of the following is correct Anonymous Quiz 26 a The kinetic energy of a system cannot be changed without changing the momentum 43 b The kinetic energy of a system can be changed without changing the momentum 21 c The momentum of a system cannot be changed without changing its kinetic energy 10 d A system cannot have energy without having momentum

7 A man drags a block through 10 m on rough surface 0 5 A force of 3 kN acting at 30 to the horizontal The work done by applied force is 2019 a zero c 5 kJ b 7 5 kJ d 10 kJ

The potential energy of a particle of mass 5 kg moving in xy plane is given as U 7x 24y joule x and y being in metre Initially at t 0 the particle is at the origin 0 0 moving with a velocity of 8 61 23 21 ms Then The velocity of the particle at t 4s is 5 ms 1 The acceleration of the particle is 5 ms The direction of motion of the particle initially at t 0 is at right angles to the direction of acceleration The path of the particle is circle

A is a fixed point at a height above a perfectly inelastic smooth horizontal plane A light inextensible string of length has one end attached to A and other to a heavy ball The ball is held at the level of A with string just taut and released from rest The speed of ball jus Find n Neglect the size of the heavy ball when compared to length ignore air resistance 9 after striking the plane is n times

The non conservative force propelling a 1 70 x 10 kg car up a mountain road does 6 70 x 10 J of work on the car The car starts from rest at sea level and has a speed of 27 0 m s at an altitude of 1 70 x 102 m above sea level Obtain the work done on the car by the combined forces of friction and air resistance both of which are non conservative forces Number Units

n A radioactive nucleus of mass M emits a photon 24 of frequency v and the nucleus recoils The recoil energy will be 1 Mc hv 2 h v 2Mc 3 Zero 4 hv The maximum number of possible interference 25 3 m 4X un ferifica anfan at a f 1 Mc hy 3 Zero am ir 4 Y m 4 n 2 of the fire affer 2 h v 2Mc 4 hv

A uniform chain of length 2 mis kept on a table such that a length of 60 cm hangs freely from the edge of the table The total mass of the chain is 4 kg The work done in pulling the entire chain on the table Take g 10 m s a 12 9 J 3 6 J c b 6 3 J d 2 0 J

4 m s opposite to 4 4 m s in original direction 20 A particle is released from rest at origin It moves under the influence of potential field U x 3x Its kinetic energy at x 2 is 2J K 2 1 5 J 13 4 Zero CAMERA Ses 2011 dx 21 3 1 0 The 1 2 3 4 1001 100

Two blocks of masses 2 9 kg and 1 9 kg are suspended from a rigid support S by two inextensible wires each of length 1 m The upper wire has negligible mass and the lower wire has uniform mass of 0 2 kg m The whole system of blocks and support has an upward acceleration of 0 2 m s Acceleration due to gravity is 9 8 m s The tensions at the midpoints of lower and upper wires are respectively given by a 30 N 50 N c 30 N 30 N b 50 N 30 N d 50 N 50 N S 1 9 kg 2 9 kg

Potential energy function describing the interaction between two atoms of a diatomic molecule is U r 1 2 1 1 2 b Force acting between them will be zero when the distance between them would be

Question 13 A marble moving with some velocity collides perfectly elastically head on with anothermarble at rest having mass 1 5 times the mass of the colliding marble The percentageof kinetic energy by the colliding marble after the collision is a 4 b 25 hs c 44 d 67 Question 14 A body of mass 100 kg falls from a height of 10 m Its increase in kinetic energy is

Question 12 A man of 60 kg weight is standing at rest on a platform He jumps up vertically a distance of 1 m and the platform at the same instant moves horizontally forward withthe result that the man lands 1 meter behind the point on the platfrom from where thetook the jump the total work done by the man at the instant he lands is a 300 J b 150 J c 600 J d zero

A particle of mass 3 kg is taken along ABCDE from A to E Height of B C D are 5m 4m 6m respectively Total path length is 20m AE 10m 0 6 Find work done to slowly move mass from A to E g 10m s B O 360J 200 J 180 J E

26 The potential energy of a system increases if work is done a upon the system by a nonconservative force b by the system against a conservative force c by the system against a nonconservative force d upon the system by a conservative force

A particle moves toward x 0 under the influence of a potential V x Alx n where A 0 and n 0 The particle has barely enough energy to reach x 0 For what values of n will it reach x 0 in a finite time 01 2

A bead under the influence of gravity slides down a frictionless wire whose height is given by the function y x Assume that at position x y 0 0 the wire is vertical and the bead passes this point with a given speed vo downward What should the shape of the wire be that is what is y as a function of x so that the vertical speed remains vo at all times Assume that the curve heads toward positive x If the shape is given by y 3gvox Fill 3a 3 in OMR sheet Bg

Abody of mass 4 m is lying in X Y plane at rest It suddenly explodes into three pieces Two pieces each of mass m move perpendicular to each other with speeds V and 2V The total kinetic energy generated due to explosion is 1 3 15 my 4 35 mv 4 2 25 mv 4 4 45 mv 8

If two point positive charges Q are tied to spring at it s two ends and charges are in equilibrium at seperation d between them Natural length of spring is and its spring constant is k Neglect gravity and gravitational interaction between charges A Elongation in spring B Elongation in spring C Compression in spring C Compression in spring 4ed k 46 k 4td k 4 k

The total mechanical energy of the roller coaster cart below at Point A is 180 000 J The speed of the cart at Point B is 20 m s Assume no energy is lost due to dissipative forces such as friction 20m Ground B C m

Pete Zaria works on weekends at Barnaby s Pizza Parlor His primary responsibility is to fill drink orders Customers He fills a pitcher full of Cola places it on the counter top and gives the 2 6 kg pitcher a 7 8 M forward push over a distance of 36 cm 0 36 m to send it to a customer at the end of the counter The coefficient of friction between the pitcher and the counter top is 0 25 a Determine the work done by Pete on the pitcher during the 36 cm push b Determine the work done by friction upon the pitcher c Determine the total work done upon the pitcher d Determine the kinetic energy of the pitcher when Pete is done pushing it e Determine the speed of the pitcher when Pete is done pushing it Choose Choose Choose Choose

9 An 38 g rifle bullet traveling at 410 m s buries itself in a 5 kg pendulum hanging on a 3 2 m long string which makes the pendulum swing upward in an arc Determine the maximum vertical displacement of the pendulum height g 9 8 m s meters

6 A basketball whose mass is 0 660 kg falls from rest through a height of 5 60 m and then bounces back On its way up it passes by a height of 3 70 m with a speed of 2 60 m s How much energy is lost during the bounce

Listen V IR Series Circuits VT V V V 1 T 1 1 13 RT R R R 1 39 0 35 E Pt 0 69 0 03 P IV C rPt Parallel Circuits VT V V V3 17 1 12 13 1 1 1 RT R R A computer monitor has a power rating of 0 240 kW How much does is cost to operate the monitor for one day if the cost of electricity is 0 12 kWh 1 R3

A roller coaster car is starting from rest from a height of 54 m as shown in the image below Assume that this is an ideal roller coaster and that there is no friction between the car and track and no air resistance a What is the maximum speed of the roller coaster 2 b The minimum speed required to clear the top of the loop safely is 18 m s What is the height of the loop 3

Question 14 3 points If the power of a motor is rated at 5 60 kW how much work can the motor do in 20 0 min

A 3 25 kg block of silver is dropped from rest at a height of 75 0 meters One third of the potential energy is converted into hear energy which raises the temperature of the silver The specific heat of silver is 234 joules per kilogram per Celsius degree What is the increase in temperature of silver a 1 05 C b 2 32 C c 3 14 C d 3 73 C

Please provide full solution to the following problems Question 12 5 points A 7 00 kg object is being pushed forward horizontally by a person with a force of 25 0 N acting at an angle of 20 0 below the horizontal It is pushed forward on a flat surface for 5 00 m a Determine the work done on the object by the person 2 b If the force of friction acting on the object is 11 6 N calculate the total work d on the object 3

spring compressing it by 0 175 m k x 0 I Xmax I m y 0 y 0 The left end of a horizontal spring is attached to a vertical wall and when released the block travels across a horizontal surface and up an incline Neglecting friction find the block s maximum height in m if the spring constant is k 645 N m The acceleration of gravity is g 9 80 m s

3 Using your calculation in question 2 calculate how long it would take this person to burn a 250 Calorie iced mocha Remember 1 Calorie 4184 J Mass 70 kg Height of Stairs 4 5 m Time 1 3 82 s Time 2 3 94 s Time 3 3 70 s

It is moving day and you are moving your thing to instead of picking up a heavy bot a new place You decia Rope around it and pull it towards the to tie a main door You apply 360 15 along the Rope that Horizontal If the box moved How much work did you do a above force of 124 N the distence of 5 3 m

1 Calculate potential gravitational energy for a 3 kg object that is falling from a height of 20 m 2 A 10 kg object is thrown to a height of 3 m When the object reaches its heigh how much gravitational potential energy does it have

2 Points DETAILS SERCP11 5 2 P 015 A 7 80 g bullet moving at 500 m s penetrates a tree trunk to a depth of 4 70 cm a Use work and energy considerations to find the average frictional force that stops the bullet N MY NOTES ASK YOUR

ground The track then drops to the ground Find the velocity of the cart once it reache A 1 5 kg cart is moving on a track with a velocity of 5 m s at a height of 7 m abov the ground 27

Which situation describes the highest rate of power A An engine does 50 joules of work in 3 seconds B An engine does 100 joules of work in 3 seconds C An engine does 50 joules of work in 2 seconds OD An engine does 100 joules of work in 2 seconds SUBMI

A carpet runner is placed onto a long straight inclined plane parallel to the steepest line in the plane from the bottom of the slope till its top The carpet is thin and flexible and it cannot slide down because of the friction but it can easily be lifted it does not stick to the plane The top end of the carpet is rolled a bit and this hoop of carpet is released The hoop rolls down the slope with greater and greater speed while its diameter increases and finally it reaches the bottom of the slope during a time of t If a solid cylinder is released at the top of the slope it reaches the bottom in a time of t The ratio Jk Find k t G

the ground with an initial speed 124 of v at an angle 0 with horizontal The average velocity of the particle between its point of projection and highest point of trajectory is 1 1 2 cos 3 1 3 cos 0 From the top of 2 2 cos e 4 v cos 0 af faa for en ufor en an 1 1 2 cos 0 3 1 3 cos 0 P dr usio 2 2 cos 2 4 v cos 0

In a resonance tube experiment a closed organ pipe of length 120 cm resonates when tuned with a tuning fork of frequency 340 Hz If water is poured in the pipe then given velocity of sound in air 340 m s neglect end correction ych 3gar ad gu 120 cm 340 Hz zka H mu dulu ula ad ug ujaka sta 1 4ft 939 va s 33m a aa fu ay eaf n 340 m s firi i247 ch T U HI U A Minimum length of water column to have the resonance is 45 cm 3336 1 fag ud G A Yad at 45 cm Correct Answer B Minimum length of water column to have the resonance is 50 cm a a Edry Ydo 50 cm C The distance between two successive nodes is 50 cm 4 a Azu 4 4 50 cm Correct Answer D The maximum length of water column to create the resonance is 95 cm A Cat A ufuca 95 cm

2 114 In the figure shown the block slides along the Q 114 ffa ich fat smooth cylindrical surface and covers a certain distance on the horizontal surface before coming to rest The work to be done by external force to return the object to initial position along the same path is U O 1 mgR 3 Rough horizontal surface 2mgR 3 2 2mgR mgR 4 4 full After GRI HRA U 0 R 1 mgR 3 2mgR 3 H a fer fer arg ff Rough horizontal surface 2 2mgR mgR 4

The intensity of gravitational field in a region is given as 7 31 41 N kg A point mass of 1 kg is moving along a 3i line so that work done by given field is zero then equation of straight line will be y 3x 2 2x 3y 2 4x 3y 2 4y 3x 4

Kinetic energy potential energy and total mechanical energy of a body are K U and E respectively Which option can not be possible E K E K

Old naval ships fired 13 kg cannon balls from a 240 kg cannon It was very important to stop the recoil of the cannon since otherwise the heavy cannon would go careening across the deck of the ship In one design a large spring with spring constant 2 0x10 N m was placed behind the cannon The other end of the spring braced against a post that was firmly anchored to the ship s frame Part A What was the speed of the cannon ball if the spring compressed 52 cm when the cannon was fired Express your answer to two significant figures and include the appropriate units BWAN HA DMC

A 1000 kilogram car accelerates at 20 m s up a 3 incline Calculate the required power in h while ignoring friction Select the correct response 7 9 hp 8 3 hp 6 9 hp

Internal forces can change 1 the linear momentum but not the kinetic energy of the system 2 the kinetic energy but not the linear momentum of the system 3 linear momentum as well as kinetic energy of the system 4 neither the linear momentum nor the kinetic energy of the system

4 62 A block weighing 1 kg is released from rest at point A on a track which is one quadrant of a circle of radius 1 2 m as shown in figure 4 144 It slides down the track and reaches point B with a velocity of 3 6 m s From the point B it slides on a level surface a distance of 2 7 m to point C where it comes to rest a What was the coefficient of friction on the horizontal surface b How much work was done against friction as the body slid down the circular track from A to B A B Figure 4 144 C

A jet of water strikes with a velocity of 35 m s a flat plate inclined at 30 with the axis of the jet If the cross sectional area of the jet is 25 cm determine i The force exerted by the jet on the plate ii The components of the force in the direction normal to the jet iii The ratio in which the discharge gets divided PTAG after striking the plate

A particle is projected vertically upwards with a speed of 16m s after some time when it again passes through the point of projection its speed is found to be 8m s It is known that the work done by air resistance is same during ascending and descending Then the maximum height attended by the particle is take g 10m s C C

A block of mass m is kept on a horizontal surface At x 0 the block is acted upon by a horizontal force F a bx The coefficient of friction between the block and surface Then a is 2mg a A work done by force F when net work done on the block is zero may be 2b a B Acceleration of block when net work done on the block is zero may be 2m a C Displacement of block when net work done on the block is zero may be b block in zoro may be a 1

The maximum possible acceleration of a train starting from the rest and moving on straight track is 10 m s and maximum possible retardation is 5 m s2 The maximum speed that train can achieve is 85 m s Minimum time in which the train can complete a journey of 1000m ending at rest is n Where n is integer Find n 2 3 sec