Work
What is the formula for work?
W=F*d*cos(theta)
What is the equation for (gravitational) potential energy?
U_g =m*g*h
What is the equation for kinetic energy?
K = 1/2 mv^2
What is the unit for work and energy
Joule
Suzie pushes a crate with 200 N of force across her 7-meter long living room. How much work does Suzie do on the crate?
Suzie does 1400 J of work.
Suzie brought a 3 kg crate to her apartment and did 795 J of work on it. How high is Suzie's apartment?
About 27 meters high.
Suzie does 230 J of work on a crate (2 kg) traveling on a flat icy surface. Assuming there is no friction, how fast is the crate going if it started from rest?
About 15 meters per second.
Consider the following roller coaster. Assuming the velocity of the cart is 0 m/s at the top of the very first hill, how fast is the cart going when it reaches the top of the first loop? Ignore friction.
About 11 m/s
Suzie is pulling a sled traveling at constant velocity with 40 N of force applied. She travels 58 meters to the start of the sledding hill. How much work is she doing on the sled?
About 2320 Joules
Suzie is planning to climb Mount Kilimanjaro (5895 meters). There's a steep (but short) trail, and a longer trail with a moderate slope. She's trying to determine which one will take more work. What trail should she take?
Both trails will require the same amount of work.
Suzie pushes a crate at constant speed doing 450 J of work on it. How fast is the crate going at the end of this, assuming the crate starts at 1 m/s?
1 m/s. The same speed as before since the the crate is moving AT CONSTANT SPEED.
Consider the following roller coaster. Assuming the velocity of the cart is 2 m/s at the top of the very first hill, how fast is the cart going when it reaches the top of the second loop? Ignore friction.
About 14 meters per second.
Suzie is pulling a sled traveling at constant velocity with 40 N of force applied. She travels 58 meters to the start of the sledding hill. How much work is friction doing on the sled?
About -2320 Joules (taking energy away from the system)
Consider the following roller coaster. What is the potential energy at the top of the very first hill?
About 73600 Joules.
Suzie pushes a crate (2 kg) from rest, doing 450 J of work on it, on a frictionless surface. How fast is the crate going at the end of this?
About 21 meters per second.
You brought your phone (137 grams) to the top of the Grand Canyon (1857 meters) to take pictures of the view, and you accidentally drop it when you get to the top. How fast is your phone going right before it hits the water? Assume you lose 200 J to air resistance.
About 183 meters per second!
A 2300-kg truck traveling at 30 m/s comes to a complete stop. The truck experiences a net average force of 12500 N. How far (distance) did the truck travel before coming to a complete stop?
About 83 meters.
You brought your phone (137 grams) to the top of the Grand Canyon (1857 meters) to take pictures of the view. How much work did you do on the phone?
About 2500 Joules.
Suzie pushes a crate (2 kg), doing 450 J of work on it, on a frictionless surface. How fast is the crate going at the end of this, assuming the crate starts at 3 m/s?
About 11.6 meters per second.
Consider the following roller coaster. The velocity of the cart is 5 m/s at the top of the very first hill. By the time it gets to the end of the ride, it has lost 60% of the original energy. Will it be going faster, slower, or the same as when it started?
It will be traveling at almost 10 meters per second, faster than the 5 m/s it started with.