1-5 work and energy (knowledge)
When a car is braked to a stop, its kinetic energy is transformed to
Heat
A child is sledding down a gently-sloped hill and slowing down. Which one of the following statements is true of the child?
Its kinetic energy is decreasing
An object is moving horizontally and increasing its speed. Which one of the following statements is true of the object?
Its potential energy is constant
An object is moving uphill and slowing down. Which one of the following statements is true of the object?
Its potential energy is increasing
A ball rolling on the ground.
KE
A car is traveling 45 mph.
KE
equation for KE
KE=1/2(m)(v^2)
A car is resting at the top of a hill.
PE
A rock is on a ledge 5 meters high.
PE
units for KE
joules(J)
units for mass
kilograms/ grams (kg/g)
An object may have potential energy because of its
location
units for velocity
m/s (v)
An object that has kinetic energy must be
moving
What task requires the most work; lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?
same
After rolling halfway down an incline a marble's kinetic energy is
the same as its potential energy
If you push an object twice as far while applying the same force, you do
twice as much work