Homework Statement
A person running in a race has to pick up a mass equal to her own mass. Assuming she can still do the same
amount of work, her speed will be changed by a factor of
a. 0.25
b. 0.50
c. 0.71
d. 1
e. 2
Homework Equations
E=1/2mv2
The Attempt at a Solution
Since m is...
Homework Statement
A farmhand does 972 J of work pulling an empty hay wagon along level ground with a force of 310 N [23 degrees below the horizontal]. A frictional force of 280 N opposes the motion. The distance the wagon travels is
a. 0.39 m
b. 1.7 m
c. 3.4 m
d. 32 m
e. 1.8 x 102 m
Homework...
I'm not sure which category this post actually belongs to, or if the title of this post is even accurate. I guessed Calculus was the closest one.
I watched this video on the web after a professor told me this mathematical phenomenon (http://www.youtube.com/watch?v=w-I6XTVZXww). It asserts...
Homework Statement
Two girls pull a sled across a field of snow, as shown in the diagram. A third girl pulls backward with a 2.0 N force. If the mass of the sled is 10 kg, determine its instantaneous acceleration.
Homework Equations
F=ma
The Attempt at a Solution
Sorry, I'm stumped.
Homework Statement
A quarterback is running across the field, parallel to the line of scrimmage, at a constant speed of 2.5m/s, when he spots an open, stationary receiver straight downfield from him (ie, in a line parallel to the sidelines). If he can throw the football at a speed of 8.0m/s...
Homework Statement
A car is slowing down at a rate of 20 km/h/s. How far does it travel if its original velocity is 50 km/h and its final velocity is 5.0 m/s?
Homework Equations
vf2 = v02 + 2aΔx
The Attempt at a Solution
vf2 = v02 + 2aΔx
Δx = (vf2 - v02) / 2a
= (182-502) /...
Homework Statement
An object thrown up from a cliff 10 m/s reaches a velocity of 20 m/s [down] as it lands. If acceleration due to gravity is 9.8 m/s2, what is the object's displacement? How long did it take for the object to land from the time it was thrown?
Homework Equations
I'm not...
Homework Statement
A book falls off a shelf and lands on the floor. Which is greater, the book's average speed or its instantaneous speed right before it lands?
Homework Equations
v = d/t
The Attempt at a Solution
I think its the instantaneous speed because the book accelerates...
With a budget of less than $100, does anyone have an idea on how to make a cheap piezoelectric generator using materials found at home?
(aluminum foil, wire, battery, and a silicon swim cap maybe?)
I plan to modify this generator to then integrate it inside a bike tire so that whenever I ride...
I'm pretty sure it cannot, but if I put a common bar magnet close to another magnet, they will move towards each other. I don't have much of a background in physics, but it seems to me that the kinetic energy is coming out of...nowhere. I can repeat this experiment as many times as I like but...
Archimedes' Principle states: "Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object."
If this is true, why then, when you take a bowling ball and submerge it in water, and take a rubber ball of the same size and...
Homework Statement
In this pattern, what is the algebraic expression for the term t?
-15, 30, 90, -360
Homework Equations
t= term number
The Attempt at a Solution
no idea
Is it possible that an object changes velocity immediately?
For example, Object A is ALWAYS travelling at a constant velocity (say 100mph). Its velocity never changes.
If Object B (which is at rest) were in the path of Object A and Object A were to slam into Object B, would Object B...
Why does the Earth orbit the Sun, but the Moon pull on Earth's tides? Earth orbits the sun, proving that the Sun has a greater gravitational pull on the Earth than the Moon. However, the Moon control's Earth's tides (unlike the Sun), which proves the opposite-the Moon has a greater...