Work
This is the formula for work.
W=F x d d=displacement; meters F=Force; Newtons
What is an example when an object has gravitational potential energy
Any time it is above the ground or Any time it has a measurable height.
What are the SI units for power?
Watts
If an object starts from a certain height at rest, what can we say about the GPE at the top and KE right before the object hits the ground?
They are equal.
What is the unit for work?
Joules (J)
This/These are the type(s) of energy a ball that was falling has the instant before it hits the ground.
kinetic energy
What is the difference between energy and power?
work and energy don't involve time, but power does (power is a rate)
What is potential energy?
Energy stored in an object
A 15 kg object is at rest 3.0 m above the ground. What is its KE right before hitting the ground?
PE=KE, 15 x 3 x 9.8 = 441 J
An object moves 10m while moving at a constant velocity of 3 m/s. How much work is done?
0 J (there is no force applied)
This/These are the type(s) of energy a ball rolling down a hill has.
kinetic and gravitational potential energy
What is the formula for power
P=W/T
What is the formula for GPE?
PE=mgh
A 300 kg roller coaster is travelling 30 m/s at the bottom of a hill. Assuming it started from rest, what was the GPE of the coaster?
135000 J
A 30 N force is applied to an object to move it 20 m. How much work is done?
600 J
A ball that is slowing down while rolling on a flat surface involves this/these type(s) of energy.
kinetic and thermal energy
Who generates more power? Spencer walking up the 20 m high staircase carrying his backpack in 10 seconds, or John running up the same staircase carrying a backpack in 3 seconds?
John because he climbed the same height in less time
What is the formula for KE?
KE=1/2MV^2 (Joules)
A roller coaster is travelling 30 m/s at the bottom of a hill. Assuming it started from rest, what was the height of the hill?
45.9 m
A man climbs up a 20 m heigh flight of stairs before realizing they forgot something and heads back down the stairs. How much work was done by the man?
o J (no work) because the displacement is 0 m (+ 20 m and -20 m)
What is the law of conservation of energy.
Energy is never created, lost, or destroyed. Only transformed.
A runner runs up a flight of stairs using 200J of work in 10 sec. How much power did that runner generate?
Power: P=W/T= 20 Watts
A 20 kg object in free fall is 2.0 m from the ground and moving at 6.0 m/s. What is the total mechanical energy of that object?
mgh + 1/2mv^2 = TME
20 x 9.8 x 2 + 1/2 x 20 x 6^2 = 752 J
A 300 kg roller coster drops from a 50 m height. At the bottom it is traveling 23 m/s. How much energy was lost? What happened to the energy?
67650 J, it transformed into heat (thermal energy)