Work Work Work Work WORK
The unit for work.
Joules
In a race, two cars have the same mass but different velocities. The car with the slower velocity has _____ kinetic energy than the other car does.
less
Electric blanket
Electrical → thermal
The amount of work done in a certain time is…
Power
Energy in motion is known as…
Kinetic energy
You move a cart of pumpkins 15 m. This requires a force of 65 N. How much work was done while moving the pumpkin?
975 J
How much energy does a 4 kg apple have that is thrown at a speed of 2 m/s?
8 J
Windmill
Kinetic → electrical
How much power is used if a 100 J of work is done to move a box in 10 s?
10 W or 10 J/s
A 0.9 kg pineapple falls from a tree that is 5.8 m tall. How much energy does the pineapple have?
51.16 J
The two conditions that must be met in order for work to be done.
1. The object must move
2. Force must be applied in the direction of the motion
I WILL read A and B:
List the type of potential energy each object below has.
A.Sandwich
B.Trampoline
A.Chemical potential energy
B.Elastic potential energy
Fireworks
Chemical → radiant/thermal/sound
How long would it take to do 36 J of work if 4 W of power are available?
9 s
How much heat is needed to warm 0.098 kg of gold from 15°C to 30°C if gold has a specific heat of 136 J/kg°C?
200 J
A small child weighs 25 N. If they do a somersault and move a distance of 3 m, how much work was done?
75 J
How much potential energy does a bird have that weighs 9 N and is sitting on a branch 3 m high?
27 J
An apple falling off a tree limb
GPE → kinetic
How much power is used if a force of 70 N is used to push a box a distance of 20 m in 5 s?
280 W
Define thermal energy and mechanical energy.
Thermal energy = the sum of kinetic and potential energy of particles in an object
Mechanical energy = the sum of kinetic and potential energy in a system
How far did you push a 12 kg barrel of tools if you did 276 J of work and pushed at a rate of 3 m/s2?
7.67 m
What is the mass of a picture that falls off a shelf 6 m high and has 150 J of energy?
2.55 kg
A man eating dinner, then tap dancing
Chemical → kinetic → sound/thermal
A motorcycle and its rider have a mass of 28 kg. If the cart accelerates at 6 m/s2 during a 40 m sprint in 100 s, how much power did the cart have?
67.2 W
What is the mass of a ball that is rolling with a speed of 26 m/s and has 1,200 J of energy?
3.55 kg