Chapter 9 Energy- physics
A 60-N object moves at 1 m/s. It's kinetic energy is...
3 J
About how efficient is a typical gasoline-burning car engine?
30%
How much power is extended if you lift a 60 N crate 10 meters in 1 second?
600 W
An arrow in a bow has 70 J of potential energy. Assuming no loss to heat, how much kinetic energy will it have after it had been shot?
70 J
How many joules of work are done on a box when a force of 25 N pushes it 3 m?
75 J
Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h?
The 60 km/h car
The unit of power is the...
Watt
How much work is done on a 60-N box of books that you carry horizontally across a 6-m room?
0 J
How much power is required to do 40 J of work on an object in 5 seconds?
8 W
An object at rest may have...
Energy
Work is defined as...
Force times distance
If Nellie Newton pushes an object with twice the force for twice the distance , she does...
Four times the work
The unit of work is the...
Joule
A ball is thrown into the air with 100 J of kinetic energy, which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, it's kinetic energy is...
Less than 100 J
Potential energy is the energy an object has because of its...
Location
An object that has kinetic energy must have...
Momentum
If an object has kinetic energy, then it also must have...
Momentum
An object that has kinetic energy must be...
Moving
Kinetic energy of an object is equal to...
One half the product of its mass times its speed squared
As a pendulum swings back and forth...
Potential energy is transformed into kinetic energy, at the lowest part of its swing its energy is all potential, kinetic energy is transformed into kinetic energy, at the end points of its swing its energy is all potential
Mechanical energy can be in form of...
Both kinetic and potential energy
Which requires more work: lifting a 70-kg sack vertically 2 meters or lifting a 35-kg sack vertically 4 meters?
Both require the same amount of work
