Homework Statement
Assume that P and S (Primary and Secondary) waves from an earthquake with a focus near the Earth's surface travel through the Earth at nearly constant but different average speeds. A monitoring station that is 1000 km from the epicenter detected the S wave to arrive at 42...
Homework Statement
Six identical books, 4.0 cm thick and each with a mass of .80 Kg, lie individually on a flat table. How much work would be needed to stack the books one on top of the other.
Homework Equations
U= mgy
The Attempt at a Solution
total mass = .8kg x 6 = 4.8...
Homework Statement
A .300-kg ball is thrown vertically upward with an initial speed of 10.0 m/s. If the initial potential energy is taken as zero, find the ball's kinetic, potential, and mechanical energy at it's initial position.
Homework Equations
1/2mv(f)^2 + mgy(f) = 1/2 mv(i)^2 +...
Homework Statement
W= f * d * Cos (theta)
Homework Equations
The Attempt at a Solution
In an object moving in the x-direction how do you know when to use zero as theta or 180 as theta? From the problems I've solved I find that when there is negative acceleration or a force...
Homework Statement
A crate is on a 20 degree plane where the coefficients of static and kinetic friction are .45 and .35 respectively. What is the acceleration of the crate?
Homework Equations
Mk= .35
Ms= .45
F= sin20 * mg (I think this is the net force?)
The Attempt at...
Homework Statement
a 2000 kg car, after its brakes are locked up, skids and comes to a rest. The coefficient of kinetic friction between rubber and pavement is 0.8. Find deceleration of the car.
Homework Equations
M= 2000 kg
W= mg
V= 0
The Attempt at a Solution
N=...
Homework Statement
The driver of a pickup truck going 100 km/h applies the brakes, giving the truck a uniform deceleration of 6.50 m/s^2 while it travels 20.0 m.
a) what is the speed of the truck in kilometers per hour at the end of this distance?
b) How much time has elapsed...
A .20- kg mass attached to a spring is pulled back horizontally across a table so that the potential energy of the system is increased from zero to 120 J. Ignoring friction, what is the kinetic energy of the system after the mass is released and has moved to a point where the potential energy...