Work Work Work Work Work
The unit of measurement for work.
What is a joule?
In a race, two cars have the same mass but different velocities. The car with the lower velocity has _______ kinetic energy than the other car.
less
Heating pad
Electrical 🡪 thermal
The amount of work done in a certain time
Power
Energy in motion
W=Fd
How much energy does a 4 kg ball have if it is thrown at a speed of 2 m/s?
8 J
Windmill
Kinetic 🡪 electrical
What unit of measurement is used to express power?
A 0.91 kg pineapple falls from a tree that is 5.8 m tall. How much potential energy did the pineapple have before it fell?
52 J
You move a cart of pumpkins 15.0 m. This requires a force of 65.0 N. How much work was done while moving the pumpkin?
975 J
List the type of potential energy each object has below:
a.) Photosynthesis
b.) Bow and arrow
a.) Chemical
b.) Elastic
Fireworks
Chemical 🡪 radiant/thermal/sound
How much power is used if 100 J of work is done to move a box in 10 s?
10 W or 10 J/s
How much thermal energy is transferred when 0.0924 kg of gold is heated from 15°C to 36 °C?
Note: Gold has a specific heat of 129 J/kg·°C.
250 J
A force of 25 N is applied to a ball to make it move 3.0 m. How much work was done?
75 J
How much energy does a bird have that weighs 9.0 N and is sitting on a branch 3.0 m high?
27 J
An apple falling off of a tree
Gravitational potential 🡪 kinetic
How long would it take to do 36 J of work if 4 W of power are available?
9 s
Define thermal energy and total (mechanical) energy.
Thermal energy = the sum of kinetic and potential energy of particles in an object
Total (Mechanical) energy = the sum of kinetic and potential energy in a system
The two conditions that must be met for work to be done
An object must move
Force applied in the direction of the motion
What is the mass of a large book that falls off a shelf 6.0 m high and has 150 J of energy?
2.6 kg
A man eating dinner, then tap dancing
Chemical 🡪 kinetic 🡪 sound/thermal
A force of 72.0 N is used to push a box a distance of 18.0 m in 4.50 s. Find power.
288 W or 288 J/s
What is the mass of a ball that is rolling with a speed of 26 m/s and has 1,200 J of energy?
3.6 kg