Ch 07: Work & EnergyWorksheetSee all chapters
All Chapters
Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
Ch 07: Work & Energy
Ch 08: Conservation of Energy
Ch 09: Momentum & Impulse
Ch 10: Rotational Kinematics
Ch 11: Rotational Inertia & Energy
Ch 12: Torque & Rotational Dynamics
Ch 13: Rotational Equilibrium
Ch 14: Angular Momentum
Ch 15: Periodic Motion (NEW)
Ch 15: Periodic Motion (Oscillations)
Ch 16: Waves & Sound
Ch 17: Fluid Mechanics
Ch 18: Heat and Temperature
Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
Ch 30: Electromagnetic Waves
Ch 31: Geometric Optics
Ch 32: Wave Optics
Ch 34: Special Relativity
Ch 35: Particle-Wave Duality
Ch 36: Atomic Structure
Ch 37: Nuclear Physics
Ch 38: Quantum Mechanics
Sections
Intro to Energy
Intro to Calculating Work
Work By Gravity & Inclined Planes
Work By Variable Forces (Springs)
Net Work & Kinetic Energy
More Work-Energy Problems
Power
LearnAdditional Practice
Next SectionMore Work-Energy Problems

Solution: A mother has four times the mass of her young son. Both are running with the same kinetic energy.What is the ratio vs/vm other of their speeds?

Solution: A mother has four times the mass of her young son. Both are running with the same kinetic energy.What is the ratio vs/vm other of their speeds?

Problem

A mother has four times the mass of her young son. Both are running with the same kinetic energy.

What is the ratio vs/vm other of their speeds?

Next
Practice Problems
A mass of 1kg begins at a position (–3 m, –4 m) at...
An 8.1 kg crate is pulled 5.1 m up a 30 incline ...
A 16-kg sled starts up a 28 incline with a speed...
Proper design of automobile braking systems must a...
You are a member of an Alpine Rescue Team and must...
An old oaken bucket of mass 6.75 kg hangs in a wel...
A factory worker pushes a crate of mass 30.1 kg a...
A factory worker pushes a 30.0 kg crate a distance...
Two blocks are connected by a very light string pa...
You push your physics book 1.80 m along a horizon...
A batter hits a baseball with mass 0.150 kg strai...
Use the work-energy theorem to solve each of these...
You throw a 3.00-N rock vertically into the air...
In the Bohr model of the atom, the ground-state el...
A cable with 21.0 N of tension pulls straight up ...
A pile driver lifts a 350 kg weight and th...
The gravitational attraction between two objects w...
Youre fishing from a tall pier and have just caugh...
A ball shot straight up with kinetic energy K0 rea...
You throw a 5.5 g coin straight down at 4.0 m/s...
The figure shows how the force exerted by the str...
The mass of a proton is 1836 times the mass of an ...
On April 13, 2029 (Friday the 13th!), the asteroid...
T. Rex. The dinosaur Tyrannosaurus rex is thought ...
At room temperature, an oxygen molecule, with mass...
Which has the larger kinetic energy, a 10 g bulle...
If the kinetic energy of a particle is tripled, by...
At what speed does a 1600 kg compact car have the...
A mother has four times the mass of her young son....
One car has twice the mass of a second car, but on...
A 3.0 g locust reaches a speed of 3.0 m/s during...
A 33.0 kg crate is initially moving with a veloci...
If a particles speed increases by a factor of 5, b...
Adult cheetahs, the fastest of the great cats, hav...
About 50000 years ago, a meteor crashed into the e...
A moving electron has kinetic energy K1 . After a ...
A ball on a string travels once around a circle wi...
A 53.0 kg ice skater is gliding along the ice, he...
A sled with mass 12.10 kg moves in a stra...
A small block with a mass of 0.0600 kg is attac...
A 0.2 kg plastic cart and a 20 kg lead cart both r...
One end of a horizontal spring with force constant...
A block of ice of mass 4.10 kg is placed against ...
A 45 g rock is placed in a slingshot and t...
You are asked to design spring bumpers for the wal...
A horizontal spring with spring constant 85 N/m ...
Chris jumps off a bridge with a bungee cord (a hea...
A 6.0-kg box moving at 5.0 m/s on a horizontal, f...
At a waterpark, sleds with riders are sent along a...
A car is stopped in a distance exttip{D}{D} by a ...
At an accident scene on a level road, investigator...
A train is moving along a track with constant spee...
A 1.50 kg book is sliding along a rough horizonta...
On an essentially frictionless, horizontal ice rin...
A 65 kg softball player slides into second...
A 12-pack of Omni-Cola (mass 4.30 kg) is initially...
A little red wagon with mass 7.10 kg moves in a st...
How much work is required to stop an electron ( m ...
A car is traveling on a level road with speed v0 a...
Your cat "Ms." (mass 7.00 kg) is trying to make it...
How much work is done by the horizontal force FP =...
Starting from rest, a crate of mass m is pushed up...
A block of ice with mass 2.00 kg slides 1.6...
A box of mass 5.5 kg is accelerated from rest by a...
An 200g object initially at rest slides 50 cm down...
How much work must be done to stop a 1300 kg car t...
A 145 g baseball traveling 33 m/s moves a fielders...
A 51.0 kg crate, starting from rest, is pulled acr...
Susan's 12.0 kg baby brother Paul sits on a mat. S...
A 6.10 kg block is pushed 9.30 m up a smooth 38.0 ...
A soccer ball with mass 0.460 kg is initially movi...
A block of mass m = 2.50 kg is pushed a distance d...
A 500 kg elevator accelerates upward at 1.3 m/s2 f...
The figure shows the kinetic-energy graph for a 2....
A 400 g particle moving along the x-axis experienc...
A box with mass 5.00 kg is pulled up a 36.9° incli...
A 2.30-kg textbook is forced against a horizontal ...
A horizontal spring with spring constant 270 N/m i...
A 10 kg object slides down an incline of 30 o. If ...
Particle A has half the mass and eight times the k...
If the human body could convert a candy bar direct...
Use the work–energy theorem to solve each of these...
A truck has four times the mass of a car and is mo...
A crate of mass 10.0 kg is pulled up a rough incli...
Jonathan is riding a bicycle and encounters a hill...
Jonathan is riding a bicycle and encounters a hill...
An 80.0-kg skydiver jumps out of a balloon at an a...
An older-model car accelerates from 0 to speed v i...
A 0.600-kg particle has a speed of 2.00 m/s at poi...
Review. You can think of the work–kinetic energy t...
A 40.0-kg box initially at rest is pushed 5.00 m a...
Review. A 7.80-g bullet moving at 575 m/s strikes ...
Previous SectionWork By Variable Forces (Springs)
Next SectionMore Work-Energy Problems